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

Example Input: Problem: a and b together can complete work in 6 days . a alone starts working and leaves it after working for 4 days completing only half of the work . in how many days it can be completed if the remaining job is undertaken by b ?
Example Output: 12

Example Input: Problem: what will be the percentage increase in the area of the cube ' s surface if each of the cube ' s edges grows by 20 % ?
Example Output: 44 %

Example Input: Problem: a couple who own an appliance store discover that if they advertise a sales discount of 10 % on every item in the store , at the end of one month the number of total items sold increases 15 % . their gross income from sales for one month increases by what percent ?
Example Output:
3.5 %