The task is to generate the correct answer for a given math problem.

Q: Problem: the average of first six prime numbers greater than 20 is ?

A: 3
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Q: Problem: mixture contains alcohol and water in the ratio 4 : 3 . if 5 liters of water is added to the mixture , the ratio becomes 4 : 5 . find the quantity of alcohol in the given mixture .

A: 10
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Q: Problem: the population of a town is 8000 . it decreases annually at the rate of 10 % p . a . what was its population 2 years ago ?

A:
9876
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