SOLUTION: one pipe can fill a tank in 3 minutes and a second pipe can fill the same tank in 7 minutes. how long will it take the two pipes to fill up this tank together?

Question 410339: one pipe can fill a tank in 3 minutes and a second pipe can fill the same tank in 7 minutes. how long will it take the two pipes to fill up this tank together?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add the rates of filling:
(1 tank filled/3 min) + (1 tank filled/7 min) = (1 tank filled / x min)

Multiply both sides by

both pipes together take 2.1 minutes
check answer:

OK
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