Four years ago a man was 6 times as old as his son. After 16 years he will be twice as old as his son. What is the present age of man?

Question: Four years ago a man was 6 times as old as his son. After 16 years he will be twice as old as his son. What is the present age of man?

Solution:
Let age of son 4 years ago be = X
So, age of man 4 years ago would be = 6X

As per question after 16 years;
2 × age of son = age of man
∴ 2(X + 4 +16) = (6X + 4 + 16)
⇒ 2X + 40 = 6X + 20
⇒ 2X - 6X = 20 - 40
⇒ - 4X = - 20
∴ X = 5

∴ Present age of man = 6X + 4 = 6 × 5 + 4 = 30 + 4 = 34 years