SOLUTION: a tank can be filled by three pipes separaely in 20, 30, and 60 minutes respectively. In how many minutes can it be filled by the three pipes working together?

Question 608581: a tank can be filled by three pipes separaely in 20, 30, and 60 minutes respectively. In how many minutes can it be filled by the three pipes working together?
Found 2 solutions by nerdybill, solver91311:
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
a tank can be filled by three pipes separaely in 20, 30, and 60 minutes respectively. In how many minutes can it be filled by the three pipes working together?
.
Let x = time (minutes) it takes for all three
then
x(1/20 + 1/30 + 1/60) = 1
multiplying both sides by 60:
x(3 + 2 + 1) = 60
x(6) = 60
x = 60/6
x = 10 minutes
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!

If A can do a job in x time periods, then A can do of the job in 1 time period. Likewise, if B can do the same job in y time periods, then B can do of the job in 1 time period. For this problem you will need C doing of the job in 1 time period

So, working together, they can do

of the job in 1 time period.

Therefore, they can do the whole job in:

time periods.

John

My calculator said it, I believe it, that settles it

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