Answer:
His son present age is 20 years
His present age is 40 years
Explanation:
Assume that this son's age now is x years
∵ His son's age now = x years
∵ Ankit age is twice as old as his son
→ Twice means × 2
∴ Ankit age = 2 × x = 2x years
→ In for years means after 4 years (add)
∵ His age in four years = 2x + 4
→ 9 years ago means before 9 years (subtract)
∵ His son 9 years ago = x - 9
∵ In 4 years he will be four times as old as what his son was 9 years ago
→ That means 2x + 4 = 4 × (x - 9)
∴ 2x + 4 = 4(x - 9)
→ Let us solve the equation to find x
∴ 2x + 4 = 4(x) - 4(9)
∴ 2x + 4 = 4x - 36
→ Subtract 4 from both sides
∵ 2x + 4 - 4 = 4x - 36 - 4
∴ 2x = 4x - 40
→ Subtract 4x from both sides
∵ 2x - 4x = 4x - 4x - 40
∴ -2x = -40
→ Divide both sides by -2
∵
=
∴ x = 20
∵ x represents the present age of his son
∴ His son present age is 20 years
∵ 2x represents his present age
∵ 2(20) = 40
∴ His present age is 40 years