# Water reservoir

One drain hole emptied the water from the tank for 20 hours, with the second drain for 30 hours. How long will the water drain from this tank if we open two drains simultaneously?

Correct result:

t =  12 h

#### Solution:

t•(1/20 + 1/30)=1

5t = 60

t = 12

Our simple equation calculator calculates it.

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