SOLUTION: Two inlet pipes can fill the pool with water in 3 hours and the other in 5 hours.An outlet pipe can empty the same pool in 6 hours.Given that the three pipes were open for 2 hours,

Question 1020437: Two inlet pipes can fill the pool with water in 3 hours and the other in 5 hours.An outlet pipe can empty the same pool in 6 hours.Given that the three pipes were open for 2 hours,what part of the work was done?pls help with a little explanation.Thanks in advance and more power....
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add rates of filling and subtract rates
of draining
Rate for 1st inlet pipe:
[ 1 pool filled ] / [ 3 hrs ]
Rate for 2nd inlet pipe:
[ 1 pool filled ] / [ 5 hrs ]
Rate for outlet pipe:
[ 1 pool drained ] / [ 6 hrs ] ( subtract this rate )
Rate for all 3 pipes open:
[ fraction of the pool filled ] / [ 2 hrs ]
--------------------------------
I can write the equation:

Multiply both sides by

11/15 of the pool got filled in 2 hrs
-------------------------------
Note that in 3 hrs, the pool is overflowing, since

( overflowed by )
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