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

Example Input: Problem: for any integer n greater than 1 , n * denotes the product of all the integers from 1 to n , inclusive . how many prime numbers are there between 6 * + 2 and 6 * + 6 , inclusive ?
Example Output: none

Example Input: Problem: gopi gives rs . 90 plus one turban as salary to his servant for one year . the servant leaves after 9 months and receives rs . 60 and the turban . find the price of the turban .
Example Output: 30

Example Input: Problem: farm tax is levied on the 25 % of the cultivated land . the tax department collected total $ 3840 through the farm tax from the village of mr . william . mr . william paid only $ 480 as farm tax . the percentage of total land of mr . willam over the total taxable land of the village is :
Example Output:
50 %