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cookiemonster26
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Please help me out with the followin questions. thanks..
correct answer is 10.8 hours
correct answer is 10.8 hours
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Rate of 1st input pipe = 1/10
Rate of 2nd input pipe = 1/8
Rate of drain = 1/6
Combined rate of 2 input pipes = 1/10+1/8
= 9/40
For the first 1/2 of the work the 2 input pipes and the drain were open so we can calculate this time (time taken for the tank to get half full)
rate * time = work
(9/40 - 1/6) * t = 1/2
time = 60/7 (1)
Now the drain is closed and the 2 input pipes work at their combined rates to fill the other 1/2 of the tank
rate * time = work
9/40 * time= 1/2
time = 20/9 (2)
Total time = (1) + (2)
= 60/7 + 20/9
= 10.8