Ben is 4 times as old as ishaan. 6 years ago, ben was 6 times as old as ishaan.
how old is ishaan now?

The correct answer for the question that is being presented above is this one:

Let x = Ishaan's age
Let 4x = Ben's age

x = 4x

6 years ago 
x-6 = Ishaan's age
6(x-6) = Ben's age

x - 6 = 6 (x - 6)
x - 6 = 6x - 36
-5x = -30
x = 6

Ishaan's age = 6 + 6 = 12
So, Ishaan is 12 years old.