KOVSHIN=BOTTLE+GLASS; $\quad$ TWO KOVSHINS=SEVEN GLASSES; BOTTLE=CUP+TWO GLASSES; $\quad$ BOTTLE=how many CUPS?
Try to replace the BOTTLE in the first line with its equivalent in CUPS and GLASSES (see the third line).

## Solution

Let's restate the conditions of the problem:

JUG = BOTTLE + GLASS; TWO JUGS = SEVEN GLASSES; BOTTLE = CUP + TWO GLASSES; BOTTLE = how many CUPS?

From the 1st and 3rd lines, it follows that the capacity of a jug is equal to the capacity of a cup and three glasses. Comparing this equality with the 2nd line, we get that a glass contains two cups. Considering now the 3rd line, we determine that the capacity of a bottle is five cups.

## Answer

5 cups.