Question: A father is now three times as old as his son. Five years back, he was four times as old as his son. The age of the son (in years) is
[A].12
15
18
20
[A].
[B].
[C].
[D].
Answer: Option B
Explanation:
Let son’s age be x years. Then, father’s age = (3x) years.
Five years ago, father’s age = (3x – 5) years and son’s age = (x – 5) years.
So, 3x – 5 = 4 (x – 5) 3x – 5 = 4x – 20 x = 15.