Question

Mr. Smith estimates that

it will take 3 hours to fill the
pool one foot using their only
hose. If the Smith's
neighbors allow them to
borrow an additional hose,
how long will it take to fill the
pool to the five foot level?
A. 3 Hours B. 7.5 hours C.12.5 hours D. 15 hours

Answer 1

12.5

Explanation:

visualizing the hours and amount of water by foot being poured into the pool you can see that 3 and 7.5 hours is too small and 15 is too large.

Answer 2

B. 7.5 hours

Explanation:

Assuming that both hoses fill at the same rate, then by simple proportion,

To raise the pool by 1 foot of water:

1 hose ---> takes 3 hours

2 hoses ----> fills twice as fast ---> will take half the time ---> 3/2 = 1.5 hrs

Hence with 2 hoses, it will take 1.5 hours to fill 1 foot of water.

to fill 5 feet of water, we will need 1.5 hours x 5 feet = 7.5 hours