<PRE><B>Question 279698</B>
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 90 minutes.  How quickly can all three fill the pool together?  (Answer is 15 minutes - I have no clue how to even start!)

Let filling the pool be  1 job

Jim can fill the pool in 30 minutes 
Jim can do 2 jobs in 1 hour

Sue can fill the pool in 3/4 hour
She can do 4/3 of the job in 1 hour

Tony can do the job in 3/2 hours
he can do 2/3 job in 1 hour

In 1 hour all 3 together will do  2 +4/3 +2/3 of the job


They will do 12/3 of the jobs in 1 hour( they can fill the pool 4 times)

4 jobs they do in 1 hour

1 job they do in 1/4 hour or 15 minutes.



  

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