Answer:
if he can work 15 hours and must make at least 160 dollars, he'll need to work 8 hours lifeguarding and 7 hours washing cars
Step-by-step explanation:
13 x 8 = 104
8 x 7 =56
when added we get 160, and the hours are exactly 15
x + y ≤ 15
13x + 8y = 160