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

Ex Input:
Problem: two trains of length 100 meters and 200 meters are 450 meters apart . they are moving towards each other on parallel tracks , at speeds of 90 km / h and 72 km / h . after how many seconds will the trains meet ?

Ex Output:
10


Ex Input:
Problem: a , b and c start a business each investing 20,000 . after 6 months a withdrew 5000 , b withdrew 4000 and c invests 6000 more . at the end of the year , a total profit of 67,600 was recorded . find the share of b .

Ex Output:
21,600


Ex Input:
Problem: if the wheel is 14 cm then the number of revolutions to cover a distance of 1408 cm is ?

Ex Output:

a ) 16