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.
Should John spend a third hour cleaning windows?
A)Yes, because he would earn $28.
B)Yes, because the additional amount he would earn is $14, which is greater than his opportunity cost of $7.
C)No, because the additional amount he would earn is $6, which is less than his opportunity cost of $7.
D)Yes, because the additional amount he would earn is $6, which is better than earning nothing.

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.   
Should John spend a third hour cleaning windows?
A)Yes, because he would earn $28. 
B)Yes, because the additional amount he would earn is $14, which is greater than his opportunity cost of $7. 
C)No, because the additional amount he would earn is $6, which is less than his opportunity cost of $7. 
D)Yes, because the additional amount he would earn is $6, which is better than earning nothing.

Quizplus · Accepted Answer

In the third hour John spends cleaning windows he cleans 3 additional windows and earns $2 per window for a total benefit of $6. He could have spent that hour earning $7 at the store, so his opportunity cost is $7. Since $6 is less than $7, he should not clean windows for a third hour.

John Is Trying to Decide How to Divide His Time