SOLUTION: 1 pool pump takes 60 minutes to fill up a pool, another pool pump takes 40 minutes to fill up a pool, how long would it take of both pumps were used to fill up the pool?

Question 937983: 1 pool pump takes 60 minutes to fill up a pool, another pool pump takes 40 minutes to fill up a pool, how long would it take of both pumps were used to fill up the pool?
Found 2 solutions by nerdybill, stanbon:
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
1 pool pump takes 60 minutes to fill up a pool, another pool pump takes 40 minutes to fill up a pool, how long would it take of both pumps were used to fill up the pool?
.
Let t = time (minutes) it takes to fill pool with both pumps
then
t(1/60 + 1/40) = 1
multiply both sides by 120 to get:
t(2 + 3) = 120
t(5) = 120
t = 24 minutes
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
1 pool pump takes 60 minutes to fill up a pool, another pool pump takes 40 minutes to fill up a pool, how long would it take of both pumps were used to fill up the pool?
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1st pump DATA:
time = 60 min/job ; rate = 1/60 job/min
----
2nd pump DATA:
time = 40 min/job ; rate = 1/40 job/min
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Together DATA:
time = x min/job ; rate = 1/x job/min
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Equation:
rate + rate = together rate
1/60 + 1/40 = 1/x
----
40x + 60x = 40*60
100x = 2400
x = 24 minutes (time to fill the pool together)
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Cheers,
Stan H.
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