McGraw Hill Glencoe Algebra 1, 2017
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McGraw Hill Glencoe Algebra 1, 2017 View details
Extend: Graphing Technology Lab, Systems of Inequalities
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Exercise 1 Page 381

When will he earn the maximum amount?

$600

Practice makes perfect
We know that Mr. Jackson charges $75 for each car he details and $25 for each car wash. Let's write an expression for his earnings for detailing y cars and washing x cars. 75y+25xWhat combination of car washing and car detailing would earn him the most amount of money? We know that he works at most 8 hours per day. Therefore, he would definitely earn the most when working the full 8 hours. Additionally, we have been given an inequality for the time he works. y ≤ -1/3x+8 This inequality represents the amount of car washing and detailing he can do in an 8 hour day. If he works exactly 8 hours, this inequality will become an equation. This equation represents the maximum amount of money he can earn! Let's substitute y= - 13x+8 into our expression to find the maximum amount.
75y+25x
75( - 1/3x+8)+25x
-75/3x+75 * 8+25x
-25x+75 * 8 +25x
-25x+600+25x
600
Therefore, the maximum amount Mr. Jackson can earn in one day is $600.