A company produces fruity drinks that contain a percentage of real fruit juice. Drink A contains 20% real fruit juice and Drink B contains 10% real fruit juice. The company used 70 liters of real fruit juice to make 3 times as many liters of Drink A as liters of Drink B. Write a system of equations that could be used to determine the number of liters of Drink A made and the number of liters of Drink B made. Define the variables that you use to write the system.

Let's define the variables:

Let x be the number of liters of Drink A made,
Let y be the number of liters of Drink B made.

According to the problem, the company used 70 liters of real fruit juice, which can be expressed as the equation:
0.2x + 0.1y = 70

We also know that the company made 3 times as many liters of Drink A as liters of Drink B, which can be expressed as the equation:
x = 3y

These two equations form the system:
0.2x + 0.1y = 70
x = 3y