The rate at which the water is leaking is 0.2 gallons per minute.
The rate of leaking can be determined by considering the change in the amount of water over time.
When a large container holds 5 gallons of water
After 20 minutes, the gallon has 1 gallon of water left
So, the change in the amount of water = 5 - 1 = 4 gallons
To calculate the rate of leaking
Rate = Change in amount/Time interval
Rate = 4/20
Rate = 1/5
Rate = 0.2 gallons
Therefore, the rate at which the water is leaking is 0.2 gallons per minute.