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

Problem: a number x is 5 times another number y . the percentage that y is less than x is
80 %

Problem: a sum of money at simple interest amounts to rs . 815 in 3 years and to rs . 878 in 4 years . the sum is :
626

Problem: given f ( x ) = 3 x 5 , for what value of x does 2 * [ f ( x ) ] + 2 = f ( 3 x 6 )
5