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Question 525537: A swimming pool can be filled up in 4 hours by pipe A, 3 hours by pipe B, and 6 hours by pipe C. At 8:00am, these three pipes started working together. After one hour, pipe B was turned off, pipe A and C continued. What was the exact time when the swimming pool was filled up?
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! A swimming pool can be filled up in 4 hours by pipe A, 3 hours by pipe B, and 6 hours by pipe C. At 8:00am, these three pipes started working together. After one hour, pipe B was turned off, pipe A and C continued. What was the exact time when the swimming pool was filled up?
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1/4=work rate of pipe A
1/3=work rate of pipe B
1/6=work rate of pipe C
let x=time it took to fill swimming pool
Work done=work rate*time on job
x/4+x/6+1/3=100%=1
LCD=12
3x+2x+4=12
3x+2x+4=12
5x=8
x=8/5=1+3/5 hour=1 hr and 36 min
ans:
Exact time when the swimming pool was filled up: 9:36 am
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