SOLUTION: an inlet pipe on a swimming pool can be used to fill the pool in 10 hours. The drain pipe can be used to empty the pool in 15 hours. If the pool is 1/3 full and then the inlet pipe

Algebra ->  Rate-of-work-word-problems -> SOLUTION: an inlet pipe on a swimming pool can be used to fill the pool in 10 hours. The drain pipe can be used to empty the pool in 15 hours. If the pool is 1/3 full and then the inlet pipe      Log On


   

Question 806035: an inlet pipe on a swimming pool can be used to fill the pool in 10 hours. The drain pipe can be used to empty the pool in 15 hours. If the pool is 1/3 full and then the inlet pipe and drain pipe are both opened, how long from that time will it take to fill the pool?
Answer by mananth(16946) About Me  (Show Source):
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an inlet pipe on a swimming pool can be used to fill the pool in 10 hours. The drain pipe can be used to empty the pool in 15 hours. If the pool is 1/3 full and then the inlet pipe and drain pipe are both opened, how long from that time will it take to fill the pool?

Inlet pipe does 1/10 of the job in 1 hour
drain does 1/15 of the job in 1 hour
when both are open they doe 1/10 -1/15 of the job in 1 hour
=1/30 of the job in 1 hour
1/3 is full so 2/3 is empty

(2/3)/(1/30)
2/3 * 30
=20 hours