A student works two part-time jobs. He earns $7 an hour for working at the college library and $13 an hour for construction work. To save time for study, he limits his work to 25 hours a week. If he enjoys the work at the library more, how many hours can he work at the library and still earn at least $235 a week?
A) 12 hr
B) 13 hr
C) 14 hr
D) 15 hr
E) 16 hr

Question

Quizplus · Accepted Answer

Let the number of hours worked at the library be $x$ and at construction be $y$. We have $x + y = 25$ and he needs to earn at least $235, so $7x + 13y \geq 235$. To maximize $x$, minimize $y$. Solving these equations, we find that when $x = 15$, the conditions are satisfied.

A Student Works Two Part-Time Jobs