Anu is four years

Let Sunil’s age be x and Anu’s age be y.

Anu’s age = y = x + 4

Eight years ago

Sunil’s age = x – 8

Anu’s age = x + 4 – 8

y = x – 4

Anu was 3 times Sunil’s age

x – 4 = 3 (x – 8)

x – 4 = 3x – 24

2x = 20

x = 10

y = x + 4

y = 10 + 4

y = 14

∴ Sunil’s age is 10 years and Anu’s age is 14 years