SOLUTION: one pipe fills a tank in 8 minutes, another pipe can fill it in 12 minutes. find the time taken to fill the tank when both pipes are running together?

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Question 418676: one pipe fills a tank in 8 minutes, another pipe can fill it in 12 minutes. find the time taken to fill the tank when both pipes are running together?
Found 2 solutions by nerdybill, Alan3354:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
one pipe fills a tank in 8 minutes, another pipe can fill it in 12 minutes. find the time taken to fill the tank when both pipes are running together?
.
Let x = time (minutes) it takes for both
then
x(1/8 + 1/12) = 1
multiplying both sides by 24:
x(3 + 2) = 24
5x = 24
x = 24/5
x = 4.8 minutes

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
One pipe fills 1/8 of the tank per minute.
The other fills 1/12 of the tank per minute.
Together, they fill 1/8 + 1/12 per minute = 3/24 + 2/24 = 5/24
5/24 tank per minute --> 24/5 minutes per tank
= 4.8 minutes
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Use the shortcut, product/sum
8*12/(8+12) = 96/20
= 4.8 minutes