The task is to generate the correct answer for a given math problem.
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Question: Problem: two pipes a and b can separately fill a cistern in 60 minutes and 75 minutes respectively . there is a third pipe in the bottom of the cistern to empty it . if all the three pipes are simultaneously opened , then the cistern is full in 50 minutes . in how much time , the third pipe alone can empty the cistern ?

Answer: 100 min


Question: Problem: a car traveled 560 miles per tankful of gasoline on the highway and 336 miles per tankful of gasoline in the city . if the car traveled 6 fewer miles per gallon in the city than on the highway , how many miles per gallon did the car travel in the city ?

Answer: 9


Question: Problem: the population of a town is 10000 . it increases annually at the rate of 20 % p . a . what will be its population after 5 years ?

Answer:
24883