The task is to generate the correct answer for a given math problem.
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Question: Problem: gopi gives rs . 90 plus one turban as salary to his servant for one year . the servant leaves after 9 months and receives rs . 60 and the turban . find the price of the turban .

Answer: 30

Question: Problem: pipe a can fill a tank in 6 hours . due to a leak at the bottom , it takes 10 hours for the pipe a to fill the tank . in what time can the leak alone empty the full tank ?

Answer: 15

Question: Problem: the age of somu is one - third his father ' s . 7 years back he was one - fifth of his father ' s age . what is his persent age ?

Answer:
14