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Question 603733: Three water pipes are used to fill a swimming pool. The first pipe alone takes 4 hours to fill the pool, the second pipe alone takes 6 hours to fill the pool, while the third pipe alone takes 12 hours to fill the pool.
If all three pipes are turned on at the same time, how long will it take to fill the pool?
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! Three water pipes are used to fill a swimming pool. The first pipe alone takes 4 hours to fill the pool, the second pipe alone takes 6 hours to fill the pool, while the third pipe alone takes 12 hours to fill the pool. If all three pipes are turned on at the same time, how long will it take to fill the pool?
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let x=hours it takes to fill pool with all three pipes turned on
1/4 =work rate of first pipe
1/6 =work rate of first pipe
1/12 =work rate of first pipe
1/x =work rate of all three pipes turned on
..
sum of individual work rates=work rate working together.
1/4+1/6+1/12=1/x
3/12+2/12+1/12=1/x
6/12=1/x
x=2
hours it takes to fill pool with all three pipes turned on=2
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