Answer:
3.5 liters
Explanation:
If each person drinks 175 milliliters of juice we must convert mililiters to liters to determine how many liters 20 people will drink.
The amount of mililiters that 20 people will drink is:

Therefore 20 people will drink 3500 mililiters of juice.
The conversion factor from 1 mililiter to 1 L is 0.001:
Therefore for 20 people in liters:
