Ya Chenno I.v.

A cooperative receives apple and grape juice in identical barrels and produces an apple-grape drink in identical cans. One barrel of apple juice is enough for exactly 6 cans of the drink, and one barrel of grape juice is enough for exactly 10 cans. When the recipe for the drink was changed, one barrel of apple juice became enough for exactly 5 cans of the drink. How many cans of the drink will now one barrel of grape juice be enough for? (The drink is not diluted with water.)

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The first method. For one can of the drink, $1 / 6$ of a barrel of apple juice and $1 / 10$ of a barrel of grape juice are used, which means the volume of the can is $1 / 6 + 1 / 10$ of the barrel. After the recipe change, $1 / 5$ of a barrel of apple juice and $4 / 15 - 1 / 5 = 1 / 15$ of a barrel of grape juice are used for one can of the drink.

The second method. For 30 cans of the drink, five barrels of apple juice and three barrels of grape juice were used, which totals 8 barrels. According to the new recipe, 6 barrels of apple juice will be used for 30 cans. Therefore, 2 barrels of grape juice will be used. Thus, one barrel of grape juice will suffice for 15 cans.

## Answer

For 15 cans.