Jim can fill a pool carrying buckets of water in 30 minutes. Sue can do the same job in 45 minutes. Tony can do the same job in 1.5 hours. How quickly can all three fill the pool together?

A.12 minutes
B.15 minutes
C.21 minutes
D.23 minutes
E.28 minutes
I got 53 minutes, but there was no answer.

1 answer

In 1.5 hours,
Tony can do one pool
Sue can do 2 pools
Jim can do 3 pools

pools=rate*time

combined rate=6pools/1.5 hrs=4pools/hr

time=pools/rate= 1pool/(4pools/hr)=1/4 hr= 15 min