{"id":148,"date":"2016-12-27T23:19:48","date_gmt":"2016-12-28T04:19:48","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/?post_type=chapter&#038;p=148"},"modified":"2017-11-08T17:31:41","modified_gmt":"2017-11-08T22:31:41","slug":"6-1-consumption-choices","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/chapter\/6-1-consumption-choices\/","title":{"raw":"6.1 The Budget Line","rendered":"6.1 The Budget Line"},"content":{"raw":"<div class=\"bcc-box bcc-highlight\">\r\n<h3>Learning Objectives<\/h3>\r\n<div>By the end of this section, you will be able to:<\/div>\r\n<div>\r\n<ul>\r\n \t<li>Understand budget lines<\/li>\r\n \t<li>Explain price ratios<\/li>\r\n \t<li>Recreate budget lines after prices and income changes<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<h1>\u00a0The Budget Line<\/h1>\r\nTo understand how households make decisions, economists look at what consumers can afford. To do this, we must chart the consumer\u2019s budget constraint. In a budget constraint, the quantity of one good is measured on the horizontal axis and the quantity of the other good is measured on the vertical axis. The budget constraint shows the various combinations of the two goods that the consumer can afford. Consider the situation of Jos\u00e9, as shown in Figure 6.1a. Jos\u00e9 likes to collect T-shirts and movies.\r\n\r\nIn Figure 6.1a, the number of T-shirts Jos\u00e9 \u00a0will buy is on the horizontal axis, while the number of movies he will buy Jos\u00e9 is on the vertical axis. If Jos\u00e9 had unlimited income or if goods were free, then he could consume without limit. But Jos\u00e9, like all of us, faces a\u00a0<strong>budget constraint<\/strong>. Jos\u00e9 has a total of $56 to spend. T-shirts cost $14 and movies cost $7.\r\n\r\nPlotting the budget constraint is a fairly simple process. Each point on the budget line has to exhaust all $56 of Jos\u00e9's budget. The easiest way to find these points is to plot the intercepts and connect the dots. Each intercept represents a case where\u00a0Jos\u00e9 spends all of his budget on either T-shirts or movies.\r\n\r\nIf\u00a0Jos\u00e9 spends all his money on movies, which cost $7,\u00a0Jos\u00e9 can buy $56\/$7, or 8 of them. This means\u00a0the y-intercept is the point (0,8). Here, Jos\u00e9 buys 0 T-shirts and 8 movies.\r\n\r\nIf\u00a0Jos\u00e9 spends all his money on T-shirts, which cost $14,\u00a0Jos\u00e9 can buy only 4 of them ($56\/$14). This means the x-intercept is the point (4,0). Here,\u00a0Jos\u00e9 buys 4 T-shirts and 0 movies.\r\n\r\nBy connecting these two extremes, you can find every combination that\u00a0Jos\u00e9 can afford along his\u00a0<strong>budget line<\/strong>.\u00a0For example, at point R,\u00a0Jos\u00e9 buys 2 T-shirts and 4 movies. This costs him:\r\n\r\nT-Shirts @ $14 x 2<strong>\u00a0<\/strong><strong>= $28<\/strong>\r\n\r\nMovies @ $7 x 4<strong>\u00a0<\/strong><strong>= $28<\/strong>\r\n\r\nTotal = $24 + $28<strong>\u00a0<\/strong><strong>=<\/strong><strong>\u00a0<\/strong><strong>$56<\/strong>\r\n\r\nThis point indeed exhausts Jos\u00e9's budget.\r\n<figure id=\"CNX_Econ_C06_001\"><\/figure>\r\n<h2><\/h2>\r\n[caption id=\"attachment_953\" align=\"alignnone\" width=\"698\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.57.58-PM.png\" width=\"698\" height=\"608\" class=\"wp-image-953 size-full\" \/> <strong>Figure 6.1a<\/strong>[\/caption]\r\n<h2>Budget Constraints<\/h2>\r\n<span style=\"font-family: Georgia;color: #333333\">We now know that Jos\u00e9 must purchase at some point along the budget line, depending on his preferences. Note that any point within the budget line is feasible. Jos\u00e9 can spend less than $56, but this is not optimal as he can still buy more goods. Since T-shirts and movies are the only two goods, there is no ability in this model for Jos\u00e9 to save. This means that not spending his full budget is essentially wasted income. On the other hand, any point beyond the budget line is not feasible. If\u00a0Jos\u00e9 only has\u00a0$56, he cannot spend more than that. Notice that areas in the green zone are not necessarily more optimal than points along the budget line. The optimal point depends on Jos\u00e9's preferences, which we will explore when we discuss\u00a0Jos\u00e9's indifference curve. <\/span>\r\n\r\n[caption id=\"attachment_954\" align=\"alignnone\" width=\"660\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.56.18-PM.png\" width=\"660\" height=\"593\" class=\"wp-image-954\" \/> <strong>Figure 6.1b<\/strong>[\/caption]\r\n<h2>Slope<\/h2>\r\nThough we can easily just connect the X and Y intercepts to find the budget line representing all possible combinations that expend\u00a0Jos\u00e9's entire budget, it is important to discuss what the slope of this line represents. Remember, the slope is the rate of change. In economics, the slope of the graph is often quite\u00a0important. In this situation, the slope is QY\/QX. If we want to represent slope in terms of prices it is equal to Px\/PY. This can seem unintuitive at first, as we are used to seeing slope as Y\/X., but the reason this is not true for prices is because the y-axis represents quantity, not price. As we saw above, as price doubles, the quantity the consumer could previously purchase is halved.\r\n\r\nIf Jos\u00e9 is making $56:\r\n\r\nWhen the price of movies\u00a0is\u00a0<strong>$7,<\/strong>\u00a0he can buy\u00a0<strong>8<\/strong>\u00a0of them\r\n\r\nWhen the price of\u00a0movies\u00a0is\u00a0<strong>$14,<\/strong>\u00a0he can buy\u00a0<strong>4<\/strong>\u00a0of them\r\n\r\nSince price and quantity have this inverse relationship, we can use\u00a0either Px\/PY or QY\/QX to find the slope. Since price is often the information given, it is important to remember that\u00a0the slope can\u00a0be calculated either way.\r\n<h3>What Does Slope\u00a0Mean?<\/h3>\r\nThe meaning of the budget line\u2019s slope or\u00a0<strong>price ratio\u00a0<\/strong>is the same as the slope of a PPF. (The difference between these two curves is that the PPF shows all the different combinations given time a time\/production constraint, whereas a budget line shows\u00a0different combinations given budget\u00a0constraint. Otherwise, the two graphs are basically the same). This means the slope of the curve is the relative price of the good on the x-axis in terms of the good on the y-axis. The\u00a0<em>price ratio\u00a0of 2<\/em><strong>\u00a0<\/strong>means that\u00a0Jos\u00e9 must give up 2 movies for every T-shirt. Likewise, the\u00a0<em>inverse slope of 1\/2<\/em><strong>\u00a0<\/strong>means that\u00a0Jos\u00e9 must give up 1\/2 a T-shirt per movie.\r\n<h1>When Income Changes<\/h1>\r\n<span style=\"font-family: Georgia;color: #333333\">Because budget and prices are prone to change, Jos\u00e9's budget line can shift and pivot. For example, if\u00a0Jos\u00e9's budget\u00a0drops from $56 to $42, the budget line will shift inward, as he is unable to purchase the same number of goods as before.<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">To plot the new budget line, find the new intercepts:<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Budget: $42<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Price of movies: $7<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Price of T-shirts: $14<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Maximum number of movies (y-intercept): $42\/$7 =<span class=\"apple-converted-space\">\u00a0<\/span><strong><span style=\"font-family: Georgia\">6<\/span><\/strong><\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Maximum number of T-shirts (x-intercept): $42\/$14 =<span class=\"apple-converted-space\">\u00a0<\/span><strong><span style=\"font-family: Georgia\">3<\/span><\/strong><\/span>\r\n\r\n[caption id=\"attachment_955\" align=\"alignnone\" width=\"665\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.17.02-PM.png\" alt=\"screen-shot-2016-12-31-at-4-17-02-pm\" width=\"665\" height=\"572\" class=\"wp-image-955\" \/> <strong>Figure 6.1c<\/strong>[\/caption]\r\n\r\nAs a result of the shift,\u00a0<span>Jos\u00e9's budget line has shifted inward, leaving less consumption opportunities available.<\/span>\r\n<h1>When Price\u00a0Changes<\/h1>\r\n<span style=\"font-family: Georgia;color: #333333\">In addition to income changes, sometimes the prices of movies and T-shirts rises and falls. Suppose, from our original budget of $56, movies double in price from $7 to $14. Again, to plot the new graph, simply find the new intercepts:<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Budget: $56<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Price of movies: $14<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Price of T-shirts: $14<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Maximum number of movies (y-intercept): $56\/$14 =<span class=\"apple-converted-space\">\u00a0<\/span><b>4<\/b><\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Maximum number of T-shirts (x-intercept): $56\/$14 =<span class=\"apple-converted-space\">\u00a0<\/span><b>4<\/b><\/span>\r\n\r\n&nbsp;\r\n\r\n[caption id=\"attachment_956\" align=\"alignnone\" width=\"633\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.21.16-PM.png\" alt=\"screen-shot-2016-12-31-at-4-21-16-pm\" width=\"633\" height=\"563\" class=\"wp-image-956\" \/> <strong>Figure 6.1d<\/strong>[\/caption]\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">As a result of the pivot,\u00a0Jos\u00e9 has\u00a0fewer consumption opportunities available and the slope of the line changes. This has two effects:<\/span>\r\n\r\n<strong><span style=\"font-family: Georgia;color: #333333\">The Size Effect<\/span><\/strong><span style=\"font-family: Georgia;color: #333333\">: There are fewer opportunities for consumption (as a result of the price change, the purchasing power of\u00a0Jos\u00e9's dollar has fallen).<\/span>\r\n\r\n<strong><span style=\"font-family: Georgia;color: #333333\">The Slope Effect<\/span><\/strong><span style=\"font-family: Georgia;color: #333333\">: The relative price of movies is now higher, while the relative price of T-shirts is now lower.<\/span>\r\n<h1>When Price and Income Change<\/h1>\r\n<span style=\"font-family: Georgia;color: #333333\">The last type of change is when both price and income change. Suppose the price of movies increases from $7 to $12\u00a0and\u00a0Jos\u00e9's budget increases\u00a0to $63. To plot the new budget line, follow the same steps as before:<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Budget: $63<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Price of movies: $12<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Price of T-shirts: $14<\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Maximum number of movies (y-intercept): $63\/$12 =<span class=\"apple-converted-space\">\u00a0<\/span><b>5.25<\/b><\/span>\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">Maximum number of T-shirts (x-intercept): $63\/$14 =<span class=\"apple-converted-space\">\u00a0<\/span><b>4.50<\/b><\/span>\r\n\r\n[caption id=\"attachment_961\" align=\"alignnone\" width=\"718\"]<img src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-5.56.38-PM.png\" width=\"718\" height=\"619\" class=\"wp-image-961 size-full\" \/> <strong>Figure 6.1e<\/strong>[\/caption]\r\n\r\n<span style=\"font-family: Georgia;color: #333333\">These changes have interesting effects.\u00a0Jos\u00e9 now has access to some\u00a0new consumption opportunities, but many others are now unavailable. While the slope effect has clearly made the relative price of T-shirts lower, the size effect is uncertain. These effects are implicit in the income and substitution effects we will explore shortly.<\/span>\r\n<h1>Conclusion<\/h1>\r\n<span style=\"font-family: Georgia;color: #333333\">Though we understand the different ways by which consumers can exhaust their income, we have not yet discussed how to determine which bundles of goods different consumers prefer. To finish our analysis, let\u2019s take a look at Indifference Curves.<\/span>\r\n<div class=\"textbox\">\r\n<h2>Glossary<\/h2>\r\n<dl id=\"fs-idp41787328\" class=\"definition\">\r\n \t<dt><strong>Budget Constraint<\/strong><\/dt>\r\n \t<dd id=\"fs-idp35020496\"><em>all possible combinations of goods and services that can be attained given current prices and limited income <\/em><\/dd>\r\n<\/dl>\r\n<dl id=\"fs-idp41787328\" class=\"definition\">\r\n \t<dt><strong>Budget Line<\/strong><\/dt>\r\n \t<dd id=\"fs-idp35020496\"><em>a graphical representation of a consumers budget constraint<\/em><\/dd>\r\n<\/dl>\r\n<dl id=\"fs-idm51600048\" class=\"definition\">\r\n \t<dt><strong>Price Ratio<\/strong><\/dt>\r\n \t<dd id=\"fs-idp17805888\"><em>the slope of the budget line, represents the price of x in terms of good y<\/em><\/dd>\r\n<\/dl>\r\n<dl id=\"fs-idm51600048\" class=\"definition\">\r\n \t<dt><strong>Size Effect<\/strong><\/dt>\r\n \t<dd id=\"fs-idp17805888\"><em>the impact of a price change on the purchasing power of the consumer<\/em><\/dd>\r\n<\/dl>\r\n<dl id=\"fs-idm51600048\" class=\"definition\">\r\n \t<dt><strong>Slope Effect<\/strong><\/dt>\r\n \t<dd id=\"fs-idp17805888\"><em>the impact of a price change on the relative prices of good x and y<\/em><\/dd>\r\n<\/dl>\r\n<\/div>\r\n<div class=\"bcc-box bcc-info\">\r\n<h3 itemprop=\"educationalUse\">Exercises 6.1<\/h3>\r\n<strong>1.<\/strong> In the diagram below, a consumer maximizes utility by choosing point A, given BL1.\r\n\r\n<img src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.25-PM.png\" alt=\"\" width=\"245\" height=\"222\" class=\"wp-image-1293 alignnone\" \/>\r\n\r\nSuppose that both good x is normal and good y is inferior, and the budget line shifts to BL2. Which of the following could be the new optimal consumption choice?\r\n\r\na) B.\r\nb) C.\r\nc) D.\r\nd) Either B or C or D.\r\n\r\n<strong>2.<\/strong> Which of the following diagrams could represent the change in a consumer\u2019s budget line if (i) the price of good y increases AND (ii) the consumer\u2019s income decreases.\r\n\r\n<img src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.29-PM.png\" alt=\"\" width=\"438\" height=\"323\" class=\"alignnone size-full wp-image-1294\" \/>\r\n\r\n&nbsp;\r\n\r\n<\/div>","rendered":"<div class=\"bcc-box bcc-highlight\">\n<h3>Learning Objectives<\/h3>\n<div>By the end of this section, you will be able to:<\/div>\n<div>\n<ul>\n<li>Understand budget lines<\/li>\n<li>Explain price ratios<\/li>\n<li>Recreate budget lines after prices and income changes<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<h1>\u00a0The Budget Line<\/h1>\n<p>To understand how households make decisions, economists look at what consumers can afford. To do this, we must chart the consumer\u2019s budget constraint. In a budget constraint, the quantity of one good is measured on the horizontal axis and the quantity of the other good is measured on the vertical axis. The budget constraint shows the various combinations of the two goods that the consumer can afford. Consider the situation of Jos\u00e9, as shown in Figure 6.1a. Jos\u00e9 likes to collect T-shirts and movies.<\/p>\n<p>In Figure 6.1a, the number of T-shirts Jos\u00e9 \u00a0will buy is on the horizontal axis, while the number of movies he will buy Jos\u00e9 is on the vertical axis. If Jos\u00e9 had unlimited income or if goods were free, then he could consume without limit. But Jos\u00e9, like all of us, faces a\u00a0<strong>budget constraint<\/strong>. Jos\u00e9 has a total of $56 to spend. T-shirts cost $14 and movies cost $7.<\/p>\n<p>Plotting the budget constraint is a fairly simple process. Each point on the budget line has to exhaust all $56 of Jos\u00e9&#8217;s budget. The easiest way to find these points is to plot the intercepts and connect the dots. Each intercept represents a case where\u00a0Jos\u00e9 spends all of his budget on either T-shirts or movies.<\/p>\n<p>If\u00a0Jos\u00e9 spends all his money on movies, which cost $7,\u00a0Jos\u00e9 can buy $56\/$7, or 8 of them. This means\u00a0the y-intercept is the point (0,8). Here, Jos\u00e9 buys 0 T-shirts and 8 movies.<\/p>\n<p>If\u00a0Jos\u00e9 spends all his money on T-shirts, which cost $14,\u00a0Jos\u00e9 can buy only 4 of them ($56\/$14). This means the x-intercept is the point (4,0). Here,\u00a0Jos\u00e9 buys 4 T-shirts and 0 movies.<\/p>\n<p>By connecting these two extremes, you can find every combination that\u00a0Jos\u00e9 can afford along his\u00a0<strong>budget line<\/strong>.\u00a0For example, at point R,\u00a0Jos\u00e9 buys 2 T-shirts and 4 movies. This costs him:<\/p>\n<p>T-Shirts @ $14 x 2<strong>\u00a0<\/strong><strong>= $28<\/strong><\/p>\n<p>Movies @ $7 x 4<strong>\u00a0<\/strong><strong>= $28<\/strong><\/p>\n<p>Total = $24 + $28<strong>\u00a0<\/strong><strong>=<\/strong><strong>\u00a0<\/strong><strong>$56<\/strong><\/p>\n<p>This point indeed exhausts Jos\u00e9&#8217;s budget.<\/p>\n<figure id=\"CNX_Econ_C06_001\"><\/figure>\n<h2><\/h2>\n<figure id=\"attachment_953\" aria-describedby=\"caption-attachment-953\" style=\"width: 698px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.57.58-PM.png\" width=\"698\" height=\"608\" class=\"wp-image-953 size-full\" alt=\"image\" srcset=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.57.58-PM.png 698w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.57.58-PM-300x261.png 300w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.57.58-PM-65x57.png 65w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.57.58-PM-225x196.png 225w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.57.58-PM-350x305.png 350w\" sizes=\"auto, (max-width: 698px) 100vw, 698px\" \/><figcaption id=\"caption-attachment-953\" class=\"wp-caption-text\"><strong>Figure 6.1a<\/strong><\/figcaption><\/figure>\n<h2>Budget Constraints<\/h2>\n<p><span style=\"font-family: Georgia;color: #333333\">We now know that Jos\u00e9 must purchase at some point along the budget line, depending on his preferences. Note that any point within the budget line is feasible. Jos\u00e9 can spend less than $56, but this is not optimal as he can still buy more goods. Since T-shirts and movies are the only two goods, there is no ability in this model for Jos\u00e9 to save. This means that not spending his full budget is essentially wasted income. On the other hand, any point beyond the budget line is not feasible. If\u00a0Jos\u00e9 only has\u00a0$56, he cannot spend more than that. Notice that areas in the green zone are not necessarily more optimal than points along the budget line. The optimal point depends on Jos\u00e9&#8217;s preferences, which we will explore when we discuss\u00a0Jos\u00e9&#8217;s indifference curve. <\/span><\/p>\n<figure id=\"attachment_954\" aria-describedby=\"caption-attachment-954\" style=\"width: 660px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.56.18-PM.png\" width=\"660\" height=\"593\" class=\"wp-image-954\" alt=\"image\" srcset=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.56.18-PM.png 691w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.56.18-PM-300x270.png 300w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.56.18-PM-65x58.png 65w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.56.18-PM-225x202.png 225w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-3.56.18-PM-350x315.png 350w\" sizes=\"auto, (max-width: 660px) 100vw, 660px\" \/><figcaption id=\"caption-attachment-954\" class=\"wp-caption-text\"><strong>Figure 6.1b<\/strong><\/figcaption><\/figure>\n<h2>Slope<\/h2>\n<p>Though we can easily just connect the X and Y intercepts to find the budget line representing all possible combinations that expend\u00a0Jos\u00e9&#8217;s entire budget, it is important to discuss what the slope of this line represents. Remember, the slope is the rate of change. In economics, the slope of the graph is often quite\u00a0important. In this situation, the slope is QY\/QX. If we want to represent slope in terms of prices it is equal to Px\/PY. This can seem unintuitive at first, as we are used to seeing slope as Y\/X., but the reason this is not true for prices is because the y-axis represents quantity, not price. As we saw above, as price doubles, the quantity the consumer could previously purchase is halved.<\/p>\n<p>If Jos\u00e9 is making $56:<\/p>\n<p>When the price of movies\u00a0is\u00a0<strong>$7,<\/strong>\u00a0he can buy\u00a0<strong>8<\/strong>\u00a0of them<\/p>\n<p>When the price of\u00a0movies\u00a0is\u00a0<strong>$14,<\/strong>\u00a0he can buy\u00a0<strong>4<\/strong>\u00a0of them<\/p>\n<p>Since price and quantity have this inverse relationship, we can use\u00a0either Px\/PY or QY\/QX to find the slope. Since price is often the information given, it is important to remember that\u00a0the slope can\u00a0be calculated either way.<\/p>\n<h3>What Does Slope\u00a0Mean?<\/h3>\n<p>The meaning of the budget line\u2019s slope or\u00a0<strong>price ratio\u00a0<\/strong>is the same as the slope of a PPF. (The difference between these two curves is that the PPF shows all the different combinations given time a time\/production constraint, whereas a budget line shows\u00a0different combinations given budget\u00a0constraint. Otherwise, the two graphs are basically the same). This means the slope of the curve is the relative price of the good on the x-axis in terms of the good on the y-axis. The\u00a0<em>price ratio\u00a0of 2<\/em><strong>\u00a0<\/strong>means that\u00a0Jos\u00e9 must give up 2 movies for every T-shirt. Likewise, the\u00a0<em>inverse slope of 1\/2<\/em><strong>\u00a0<\/strong>means that\u00a0Jos\u00e9 must give up 1\/2 a T-shirt per movie.<\/p>\n<h1>When Income Changes<\/h1>\n<p><span style=\"font-family: Georgia;color: #333333\">Because budget and prices are prone to change, Jos\u00e9&#8217;s budget line can shift and pivot. For example, if\u00a0Jos\u00e9&#8217;s budget\u00a0drops from $56 to $42, the budget line will shift inward, as he is unable to purchase the same number of goods as before.<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">To plot the new budget line, find the new intercepts:<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Budget: $42<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Price of movies: $7<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Price of T-shirts: $14<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Maximum number of movies (y-intercept): $42\/$7 =<span class=\"apple-converted-space\">\u00a0<\/span><strong><span style=\"font-family: Georgia\">6<\/span><\/strong><\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Maximum number of T-shirts (x-intercept): $42\/$14 =<span class=\"apple-converted-space\">\u00a0<\/span><strong><span style=\"font-family: Georgia\">3<\/span><\/strong><\/span><\/p>\n<figure id=\"attachment_955\" aria-describedby=\"caption-attachment-955\" style=\"width: 665px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.17.02-PM.png\" alt=\"screen-shot-2016-12-31-at-4-17-02-pm\" width=\"665\" height=\"572\" class=\"wp-image-955\" srcset=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.17.02-PM.png 717w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.17.02-PM-300x258.png 300w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.17.02-PM-65x56.png 65w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.17.02-PM-225x194.png 225w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.17.02-PM-350x301.png 350w\" sizes=\"auto, (max-width: 665px) 100vw, 665px\" \/><figcaption id=\"caption-attachment-955\" class=\"wp-caption-text\"><strong>Figure 6.1c<\/strong><\/figcaption><\/figure>\n<p>As a result of the shift,\u00a0<span>Jos\u00e9&#8217;s budget line has shifted inward, leaving less consumption opportunities available.<\/span><\/p>\n<h1>When Price\u00a0Changes<\/h1>\n<p><span style=\"font-family: Georgia;color: #333333\">In addition to income changes, sometimes the prices of movies and T-shirts rises and falls. Suppose, from our original budget of $56, movies double in price from $7 to $14. Again, to plot the new graph, simply find the new intercepts:<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Budget: $56<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Price of movies: $14<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Price of T-shirts: $14<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Maximum number of movies (y-intercept): $56\/$14 =<span class=\"apple-converted-space\">\u00a0<\/span><b>4<\/b><\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Maximum number of T-shirts (x-intercept): $56\/$14 =<span class=\"apple-converted-space\">\u00a0<\/span><b>4<\/b><\/span><\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_956\" aria-describedby=\"caption-attachment-956\" style=\"width: 633px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.21.16-PM.png\" alt=\"screen-shot-2016-12-31-at-4-21-16-pm\" width=\"633\" height=\"563\" class=\"wp-image-956\" srcset=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.21.16-PM.png 692w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.21.16-PM-300x267.png 300w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.21.16-PM-65x58.png 65w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.21.16-PM-225x200.png 225w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-4.21.16-PM-350x311.png 350w\" sizes=\"auto, (max-width: 633px) 100vw, 633px\" \/><figcaption id=\"caption-attachment-956\" class=\"wp-caption-text\"><strong>Figure 6.1d<\/strong><\/figcaption><\/figure>\n<p><span style=\"font-family: Georgia;color: #333333\">As a result of the pivot,\u00a0Jos\u00e9 has\u00a0fewer consumption opportunities available and the slope of the line changes. This has two effects:<\/span><\/p>\n<p><strong><span style=\"font-family: Georgia;color: #333333\">The Size Effect<\/span><\/strong><span style=\"font-family: Georgia;color: #333333\">: There are fewer opportunities for consumption (as a result of the price change, the purchasing power of\u00a0Jos\u00e9&#8217;s dollar has fallen).<\/span><\/p>\n<p><strong><span style=\"font-family: Georgia;color: #333333\">The Slope Effect<\/span><\/strong><span style=\"font-family: Georgia;color: #333333\">: The relative price of movies is now higher, while the relative price of T-shirts is now lower.<\/span><\/p>\n<h1>When Price and Income Change<\/h1>\n<p><span style=\"font-family: Georgia;color: #333333\">The last type of change is when both price and income change. Suppose the price of movies increases from $7 to $12\u00a0and\u00a0Jos\u00e9&#8217;s budget increases\u00a0to $63. To plot the new budget line, follow the same steps as before:<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Budget: $63<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Price of movies: $12<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Price of T-shirts: $14<\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Maximum number of movies (y-intercept): $63\/$12 =<span class=\"apple-converted-space\">\u00a0<\/span><b>5.25<\/b><\/span><\/p>\n<p><span style=\"font-family: Georgia;color: #333333\">Maximum number of T-shirts (x-intercept): $63\/$14 =<span class=\"apple-converted-space\">\u00a0<\/span><b>4.50<\/b><\/span><\/p>\n<figure id=\"attachment_961\" aria-describedby=\"caption-attachment-961\" style=\"width: 718px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-5.56.38-PM.png\" width=\"718\" height=\"619\" class=\"wp-image-961 size-full\" alt=\"image\" srcset=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-5.56.38-PM.png 718w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-5.56.38-PM-300x259.png 300w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-5.56.38-PM-65x56.png 65w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-5.56.38-PM-225x194.png 225w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2016-12-31-at-5.56.38-PM-350x302.png 350w\" sizes=\"auto, (max-width: 718px) 100vw, 718px\" \/><figcaption id=\"caption-attachment-961\" class=\"wp-caption-text\"><strong>Figure 6.1e<\/strong><\/figcaption><\/figure>\n<p><span style=\"font-family: Georgia;color: #333333\">These changes have interesting effects.\u00a0Jos\u00e9 now has access to some\u00a0new consumption opportunities, but many others are now unavailable. While the slope effect has clearly made the relative price of T-shirts lower, the size effect is uncertain. These effects are implicit in the income and substitution effects we will explore shortly.<\/span><\/p>\n<h1>Conclusion<\/h1>\n<p><span style=\"font-family: Georgia;color: #333333\">Though we understand the different ways by which consumers can exhaust their income, we have not yet discussed how to determine which bundles of goods different consumers prefer. To finish our analysis, let\u2019s take a look at Indifference Curves.<\/span><\/p>\n<div class=\"textbox\">\n<h2>Glossary<\/h2>\n<dl id=\"fs-idp41787328\" class=\"definition\">\n<dt><strong>Budget Constraint<\/strong><\/dt>\n<dd id=\"fs-idp35020496\"><em>all possible combinations of goods and services that can be attained given current prices and limited income <\/em><\/dd>\n<\/dl>\n<dl id=\"fs-idp41787328\" class=\"definition\">\n<dt><strong>Budget Line<\/strong><\/dt>\n<dd id=\"fs-idp35020496\"><em>a graphical representation of a consumers budget constraint<\/em><\/dd>\n<\/dl>\n<dl id=\"fs-idm51600048\" class=\"definition\">\n<dt><strong>Price Ratio<\/strong><\/dt>\n<dd id=\"fs-idp17805888\"><em>the slope of the budget line, represents the price of x in terms of good y<\/em><\/dd>\n<\/dl>\n<dl id=\"fs-idm51600048\" class=\"definition\">\n<dt><strong>Size Effect<\/strong><\/dt>\n<dd id=\"fs-idp17805888\"><em>the impact of a price change on the purchasing power of the consumer<\/em><\/dd>\n<\/dl>\n<dl id=\"fs-idm51600048\" class=\"definition\">\n<dt><strong>Slope Effect<\/strong><\/dt>\n<dd id=\"fs-idp17805888\"><em>the impact of a price change on the relative prices of good x and y<\/em><\/dd>\n<\/dl>\n<\/div>\n<div class=\"bcc-box bcc-info\">\n<h3 itemprop=\"educationalUse\">Exercises 6.1<\/h3>\n<p><strong>1.<\/strong> In the diagram below, a consumer maximizes utility by choosing point A, given BL1.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.25-PM.png\" alt=\"\" width=\"245\" height=\"222\" class=\"wp-image-1293 alignnone\" srcset=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.25-PM.png 194w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.25-PM-65x59.png 65w\" sizes=\"auto, (max-width: 245px) 100vw, 245px\" \/><\/p>\n<p>Suppose that both good x is normal and good y is inferior, and the budget line shifts to BL2. Which of the following could be the new optimal consumption choice?<\/p>\n<p>a) B.<br \/>\nb) C.<br \/>\nc) D.<br \/>\nd) Either B or C or D.<\/p>\n<p><strong>2.<\/strong> Which of the following diagrams could represent the change in a consumer\u2019s budget line if (i) the price of good y increases AND (ii) the consumer\u2019s income decreases.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.29-PM.png\" alt=\"\" width=\"438\" height=\"323\" class=\"alignnone size-full wp-image-1294\" srcset=\"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.29-PM.png 438w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.29-PM-300x221.png 300w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.29-PM-65x48.png 65w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.29-PM-225x166.png 225w, https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-content\/uploads\/sites\/58\/2016\/12\/Screen-Shot-2017-02-13-at-1.39.29-PM-350x258.png 350w\" sizes=\"auto, (max-width: 438px) 100vw, 438px\" \/><\/p>\n<p>&nbsp;<\/p>\n<\/div>\n","protected":false},"author":58,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-148","chapter","type-chapter","status-publish","hentry"],"part":32,"_links":{"self":[{"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/pressbooks\/v2\/chapters\/148","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/wp\/v2\/users\/58"}],"replies":[{"embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/wp\/v2\/comments?post=148"}],"version-history":[{"count":15,"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/pressbooks\/v2\/chapters\/148\/revisions"}],"predecessor-version":[{"id":2326,"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/pressbooks\/v2\/chapters\/148\/revisions\/2326"}],"part":[{"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/pressbooks\/v2\/parts\/32"}],"metadata":[{"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/pressbooks\/v2\/chapters\/148\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/wp\/v2\/media?parent=148"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/pressbooks\/v2\/chapter-type?post=148"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/wp\/v2\/contributor?post=148"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.bccampus.ca\/uvicecon103\/wp-json\/wp\/v2\/license?post=148"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}