SOLUTION: Have tried repeatedly and can't figure this out. Please help. If Sue can fill a swimming pool in 30 mins., Paul can fill it in 45 mins. and Bob can fill the pool in 1hr.30 mins.,

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Question 213462: Have tried repeatedly and can't figure this out. Please help.
If Sue can fill a swimming pool in 30 mins., Paul can fill it in 45 mins. and Bob can fill the pool in 1hr.30 mins., How long would it take them to fill the pool if they all worked together?
Found 2 solutions by Earlsdon, josmiceli:
Answer by Earlsdon(6294) (Show Source):
You can put this solution on YOUR website!
You can start this problem by finding the rate (how much can be done in one minute) for each of the participants.
If Sue can fill the pool in 30 minutes, then she can fill of the pool in 1 minute.
If Paul can fill the pool in 45 minutes, then he can fill of the pool in 1 minute.
If Bob can fill the pool in 90 minutes, then he can fill of the pool in 1 minutes.
So in 1 minute, working together, they can fill:
= of the pool.
If they can fill of the pool in 1 minute, then it will take them 15 minutes to fill the entire pool.

Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
This is the exact same problem as: "If sue can mow a lawn
in 30 min, Paul takes 45 min, how long does it take working together
In words:
(sue's rate filling pool)+(Paul's rate)+(Bob's rate) = (rate filling pool together)
Let = time in minutes to fill pool by all 3 filling together
given:
Sue's rate is (1 pool/30 min) =
Paul's rate is (1 pool/45 min) =
Bob's rate is (1 pool/90 min) =
Rate filling together is (1 pool/x min) =
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Multiply both sides by

With all 3 filling together it takes 15 min to fill pool