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

[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 ?
[A]: 80


[Q]: Problem: if a - b = 5 and a 2 + b 2 = 31 , find the value of ab .
[A]: 3


[Q]: Problem: the grade point average of the entire class is 80 . if the average of one fourth of the class is 92 , what is the average of the rest of the class ?
[A]:
76