Three merchants' wives - Sosipatra Titovna, Olympiada Karpovna, and Polikseina Uvarovna - sat down to drink tea. Olympiada Karpovna and Sosipatra Titovna drank 11 cups together, Polikseina Uvarovna and Olympiada Karpovna - 15, and Sosipatra Titovna and Polikseina Uvarovna - 14. How many cups of tea did all three merchants' wives drink together?

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Notice, the cup drunk by each merchant's wife was mentioned twice in the problem's condition.

## Solution

|If we add up all the cups accounted for, we get twice the sum of the cups drunk. Therefore, we need to divide this sum by two.

## Answer

20 cups.