Answer: It will remove 100 gallons for water in 20 minutes.
Step-by-step explanation:
The formula use for direct variation :-
, where k is the constant rate of change.
Given : Michael has a water pump that will pump water at the rate of 5 gallons per minute.
Let x be the number of minutes and y be gallons of water it will remove .
For x = 20 minutes and k= 5 in the above formula , we get

Hence, it will remove 100 gallons for water in 20 minutes.