Bunuel wrote:

Two hoses (X and Y) are filling a pool. Working alone at their individual constant rates, Hose X could fill the pool in 6 hours and Hose Y could do it in 4 hours. If the two hoses work together to fill half the pool, and then Hose Y finishes alone, how long will it take to fill the pool?

A. 2 hours, 48 minutes

B. 3 hours

C. 3 hours, 12 minutes

D. 3 hours, 24 minutes

E. 3 hours, 48 minutes

Find the combined rate

1/6 + 1/4 = 5/12

The time it takes to fill it entirely is 12/5

Half of the pool required time is 6/5

for y alone it takes 4 hours to fill one pool.

So it takes 2 hours to fill half.

6/5 = 1 hour and 12 minutes

Total 3 hours 12 minutes

Answer choice C

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