SOLUTION: Don't know what kind of question this is.... 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

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Question 279698: Don't know what kind of question this is....
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!)
Found 2 solutions by nerdybill, mananth:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
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!
.
Rates at which each can fill the pool:
Jim: 1 pool per 30 mins
Sue: 1 pool per 45 mins
Tony: 1 pool per 90 mins
.
Let x = minutes all three can fill the pool
then
x(1/30 + 1/45 + 1/90) = 1
The 1 on the right represents 1 pool
.
Multiply both sides by 90:
x(3 + 2 + 1) = 90
6x = 90
x= 90/6
x = 15 minutes

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
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.