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

Ex Input:
Problem: the average salary of 20 people in the shipping department at a certain firm is $ 1000 . the salary of 10 of the employees is $ 600 each and the salary of 6 of the employees is $ 200 each . what is the average salary of the remaining employees ?

Ex Output:
$ 3200


Ex Input:
Problem: when the price of a product was decreased by 20 % , the number sold increased by 60 % . what was the effect on the total revenue ?

Ex Output:
28 %


Ex Input:
Problem: a man , a woman and a boy can together complete a piece of work in 3 days . if a woman alone can do it in 6 days and a boy alone in 18 days , how long will a man take to complete the work ?

Ex Output:

9 days