Egan needs to drain his 21,000 -gallon inground swimming pool to have it resurfaced. He uses two pumps to drain the pool. One drains 15 gallons of water a minute while the other drains 20 gallons of water a minute. If the pumps are turned on at the same time and remain on until the pool is drained, how long will it take for the pool to be drained?

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Mathematics

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9 December, 17:10

Egan needs to drain his 21,000 -gallon inground swimming pool to have it resurfaced. He uses two pumps to drain the pool. One drains 15 gallons of water a minute while the other drains 20 gallons of water a minute. If the pumps are turned on at the same time and remain on until the pool is drained, how long will it take for the pool to be drained?

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Krista Eaton · Answer 1

600 minutes

Step-by-step explanation:

The total rate of the Pump is gotten first

15 + 20 = total rates of 35 gallon per hour.

rate = volume / time.

Volume = rate * time

21,000 = 35 * t

t = 21,000/35

t = 600 minutes.

To check the volume each pump will pump out.

pump A 15 * 100 = 9000 gallons

Pump B 20 * 600 = 12000 gallons.

12,000+9,000 = 21,000 which gives the total gallons of the swimming pool back