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

Example Input: Problem: a swimmer can swim in still water at 4 km / h . if the speed of the water current is 2 km / h , how many hours will the swimmer take to swim against the current for 5 km ?
Example Output: 2.5

Example Input: Problem: whats the reminder when 58 , 458,965 , 231,457 , 895,684 , 525,465 , 985,445 is divided by 16
Example Output: 5

Example Input: Problem: the present worth of rs . 2310 due 2 years hence , the rate of interest being 15 % per annum , is :
Example Output:
1680