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

Example Input: Problem: a is half good a work man as b and together they finish a job in 14 days . in how many days working alone b finish the job ?
Example Output: 21

Example Input: Problem: the average weight of a group of boys is 30 kg . after a boy of weight 45 kg joins the group , the average weight of the group goes up by 1 kg . find the number of boys in the group originally ?
Example Output: 14

Example Input: Problem: the length and breadth of a rectangle is increased by 3 % and 6 % respectively . what is the increase in the area ?
Example Output:
9.18