Answer:
13 liters per minute.
Explanation:
First, notice that we're finding liters per minute. To find this rate, we have to know the number of liters, and the number of minutes.
The number of minutes is easy, and is given: 4 minutes.
To find the number of liters, subtract the 9 liters of gas in the tank from the capacity of 61 liters.
61 liters - 9 liters = 52 liters
Now, we have our two values: 52 liters per 4 minutes.
This rate simplifies to 13 liters per minute.