5. Over three days, juice was sold in the cafeteria. On the first day, 1 large and 4 medium cans were sold, on the second day - 2 large and 6 liter cans, and on the third day - 1 large, 3 medium, and 3 liter cans. How many liters of juice were sold over 3 days, if the same amount of juice was sold each day?
5. Comparing what was sold on the first and third days (I - 1 large jar and 4 medium; III - 1 large jar, 3 medium, and 3 liter jars), we get that the medium jar has a capacity of 3 liters. Therefore, for:

I day - 1 large jar and $3 \cdot 4=12$ (L);

II day - 2 large jars and 6 L. From this, the capacity of the large jar is 6 L. Thus, for one day, $6+12=18$ (L) were sold, and for three days - 54 L.