Answer:
12
Explanation:
Let Rahul's age be x now
Now:
Rahuls age = x
Rahul's father's age = 3x (given in the question)
4 years ago,
Rahul's age = x - 4
Rahul's father's age = 4*(x - 4) = 4x - 16 (given in the question)
Rahul's father's age 4 years ago = Rahul's father's age now - 4
⇒ 4x - 16 = 3x - 4
⇒ 4x - 3x = 16 - 4
⇒ x = 12