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.

answer: a.

step-by-step explanation: the answer is a. because, you need to converge the fractions to find a solution.

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.