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

[EX Q]: 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 ?
[EX A]: 170', 'c ) 1425', 'd ) 2025', 'e ) 2500'

[EX Q]: Problem: the owner of a furniture shop charges his customer 25 % more than the cost price . if a customer paid rs . 1000 for a computer table , then what was the cost price of the computer table ?
[EX A]: 80

[EX Q]: Problem: joe needs to paint all the airplane hangars at the airport , so he buys 360 gallons of paint to do the job . during the first week , he uses 1 / 4 of all the paint . during the second week , he uses 1 / 3 of the remaining paint . how many gallons of paint has joe used ?
[EX A]:
180