SOLUTION: One pump can drain a pool in 6 minutes. When a second pump is also used, the pool only takes 2 minutes to drain. How long would it take the second pump to drain the pool if it were

Algebra ->  Rate-of-work-word-problems -> SOLUTION: One pump can drain a pool in 6 minutes. When a second pump is also used, the pool only takes 2 minutes to drain. How long would it take the second pump to drain the pool if it were      Log On


   

Question 754763: One pump can drain a pool in 6 minutes. When a second pump is also used, the pool only takes 2 minutes to drain. How long would it take the second pump to drain the pool if it were the only
pump in use? (Round your answer to the nearest tenth, if necessary.)
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
One job is "drain the pool".

One pump, rate is 1%2F6 jobs per minute.
Second pump plus the one pump, rate is 1%2F2 jobs per minute.

The rates of each pump working together are simply added.

Call rate for the second pump, r.
(one pump) + (second pump)= (one pump and second pump)
highlight%281%2F6%2Br=1%2F2%29
Find r. Know that r is in units of jobs per minute and you want the RECIPROCAL.