One inlet pipe can fill an empty pool in 9 hours, and a drain can empty the pool in 15 hours. How long will it take the pipe to fill the pool if the drain is left open?

Question

Mathematics

Marely Short

7 October, 23:36

One inlet pipe can fill an empty pool in 9 hours, and a drain can empty the pool in 15 hours. How long will it take the pipe to fill the pool if the drain is left open?

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Answers (1)

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Tia Bradley · Answer 1

For every 1 liter in there is 9/15 liters out

effectively the influx is 4/15 liters

Proportion

1 liter / 9 hours = 4/15 liters / X hours

X = (4/15 liters * 9 hours) / 1 liter

X = 36 hours