John is trying to decide how to divide his time between his job as a stocker in the local grocery store, which pays $7 per hour for as many hours as he chooses to work, and cleaning windows for the businesses downtown. He makes $2 for every window he cleans. John is indifferent between the two tasks, and the number of windows he can clean depends on how many hours he spends cleaning in a day, as shown in the accompanying table.
What is the lowest price per window that John would be willing to accept to spend 4 hours per day cleaning windows?
A)$7
B)$2
C)$3.50
D)$11

Question

John is trying to decide how to divide his time between his job as a stocker in the local grocery store, which pays $7 per hour for as many hours as he chooses to work, and cleaning windows for the businesses downtown. He makes $2 for every window he cleans. John is indifferent between the two tasks, and the number of windows he can clean depends on how many hours he spends cleaning in a day, as shown in the accompanying table.   
What is the lowest price per window that John would be willing to accept to spend 4 hours per day cleaning windows?
A)$7 
B)$2 
C)$3.50 
D)$11

Quizplus · Accepted Answer

He must make at least $7 per hour cleaning windows since he can earn that amount at the grocery store. If he spends a fourth hour cleaning windows, he can clean 2 additional windows. Thus, in order to earn at least $7 in the fourth hour, he has to be paid a minimum of $3.50 per window.

John Is Trying to Decide How to Divide His Time