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

Example Input: Problem: a diagonal of a polygon is an segment between two non - adjacent vertices of the polygon . how many diagonals does a regular 20 - sided polygon have ?
Example Output: 170', 'c ) 1425', 'd ) 2025', 'e ) 2500'

Example Input: Problem: sachin is older than rahul by 7 years . if the ratio of their ages is 11 : 9 , find the age of sachin
Example Output: 38.5

Example Input: Problem: a man have 8 t - shirt and some pant . he can dress in 72 ways . then tell me the no . of pant that man have .
Example Output:
9