Let x be the age of Ben and y be the age of Ishaan.
x= 4y... Equation (1)
x= y + 6... Equation (2)
Subtract the 2 equations
(1) - (2) : x-x= 4y - (y+ 6)
0 = 4y - y - 6
0 = 3y - 6
3y = 6
y = 2
So Ishaan is 2 years old
Substitute y = 2 in equation (1)
x = 4(2)
x = 8
So Ben is 8 years old and Ishaan is 2 years old.