Hi can someone help me with this word problem? One pump can empty a swimming pool in 4 hours while a second pump can empty the same pool in 5 hours. How many hours long will it take the two pumps working together to drain the pool? Round your answer to the nearest tenth.

It takes 20/9 hours for both pumps to completely drain the pool.

Step-by-step explanation:

The rate of the first pump is emptying 1/4 of the pool in an hour.

The rate of the second pump is emptying 1/5 of the pool in an hour

The combined rate of these two per hour is

1/4 + 1/5 = 9/20

The time taken to completely drain the pool is 1 (the whole pool) divided by the combined rate. So:

9/20x = 1

x = 1/ ⁹⁄₂₀

x = 20/9

It takes 20/9 hours for both pumps to completely drain the pool.

Put this into the calculator to round to the nearest tenth.

dnji

step-by-step explanation:

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