McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
3. Inequalities in One Triangle
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Exercise 51 Page 433

Practice makes perfect
a We are told that a waiter at the five-star restaurant makes $2.50 per hour. Multiplying this value by the number of hours the waiter has worked h, we get how much he earned.
2.50h

It is also given that the waiter receives $198 in tips. This amount does not depend on the number of hours the waiter worked, so we just add it to what the waiter has already earned. 2.50h+198 This way we got the expression for the amount of money the waiter earned after working for h hours. We know that this amount is represented by t. Therefore, we get the following equation. t=2.50h+198

b It is given that the waiter earned a total of $213. In order to find the number of hours that he worked, let's substitute 213 for t in the equation from Part A. Then we will solve it for h.
t=2.50h+198
213=2.50h+198
15=2.50h
6=h
h=6
The waiter worked for 6 hours to earn $213.
c This time we are given that the waiter earned $150 instead of $198 in tips. Let's change this in the equation.
t=2.50h+ 198 ⇒ t=2.50h+ 150 Now we can substitute the number of hours the waiter worked, 12, for h in the equation. Then we will be able to solve it for t.
t=2.50h+150
t=2.50( 12)+150
t=30+150
t=180
In total, the waiter earned $180.