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

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 ?
7 %

Problem: a rectangular plot measuring 90 metres by 50 metres is to be enclosed by wire fencing . if the poles of the fence are kept 10 metres apart , how many poles will be needed ?
28

Problem: the total age of a and b is 16 years more than the total age of b and c . c is how many year younger than
16 years