Working together, 7 identical pumps can empty a pool in 5 hours. How many hours will it take 4 pumps to empty the same pool?
Pick one
A) 4 2/3	B) 9 1/4	C) 9 1/3	D) 8 3/4	E) 10 1/2
The answer is D   7 pumps take 5 hours. 1 Pump will take 5*7 hours . Hence 4 pumps will take (5*7)/4 = 8 75/100 = 8 3/4 hours
<result>D</result>
Working together, 7 identical pumps can empty a pool in 5 hours. How many hours will it take 4 pumps to empty the same pool?