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

Example Input: Problem: a lent rs . 5000 to b for 2 years and rs . 3000 to c for 4 years on simple interest at the same rate of interest and received rs . 1540 in all from both of them as interest . the rate of interest per annum is ?
Example Output: 7 %

Example Input: Problem: a fair price shopkeeper takes 10 % profit on his goods . he lost 60 % goods during theft . his loss percent is :
Example Output: 56 %

Example Input: Problem: in what time will a railway train 52 m long moving at the rate of 24 kmph pass a telegraph post on its way ?
Example Output:
8 sec