If the digits of my present age are reversed then I get the age of my son. 9…
2025
If the digits of my present age are reversed then I get the age of my son. 9 years ago my age was twice as that of my son, then present age of my son is :
- A.
36 years
- B.
46 years
- C.
24 years
- D.
45 years
Attempted by 9 students.
Show answer & explanation
Correct answer: A
Let the father's present age be 10x + y and the son's present age be 10y + x.
Nine years ago their ages were 10x + y - 9 and 10y + x - 9 respectively. The father was twice the son then, so:
10x + y - 9 = 2(10y + x - 9)
Simplify: 10x + y - 9 = 20y + 2x - 18 → 8x - 19y = -9 → 8x = 19y - 9.
Since x is the tens digit (1–9) and y is the units digit (0–9), find y such that 19y - 9 is divisible by 8. Trying y = 3 gives 19·3 - 9 = 48, so x = 48/8 = 6.
Therefore the son's present age is 10y + x = 10·3 + 6 = 36 years.