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 and a half hours. How quickly can all three fill the pool together?

Question

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 and a half hours.  How quickly can all three fill the pool together?

drwls · Answer

Add the pool-filling RATES of the three people. That would be
2 pools/hour + (4/3) pools/hr + (2/3) pools/hour = 4 pools/hour

The time required to fill one pool when working together, assuming they do not get in each others' way, is
(1 pool)/(4 pools/hr) = 1/4 h = 15 minutes.

Nicole · Answer

Ok I am still a little confused could you explain more about how you got the first part?

drwls · Answer

To get the pool filling RATE of each person, divide 1 by the time it takes to fill a pool, in hours. That is what I did. Then I added the three rates.