Answer:
15 years
Explanation:
Let Ishaan's age = x years
Ben is 4 times as old as Ishaan.
Hence, Ben's age is 4*x years
6 years ago,Ishaan's age was (x-6) years.
6 years ago,Ben's age was (4x-6) years.
6 years ago, ben was 6 times older than ishaan.
=>
=>
=>
=>
=>
=>