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

Example Input: Problem: tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random . what is the probability taht the ticket drawn has a number which is a multiple of 3 or 5 ?
Example Output: 9 / 20

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: a can do a piece of work in 4 days . b can do it in 10 days . with the assistance of c they completed the work in 2 days . find in how many days can c alone do it ?
Example Output:
20 / 3 days