UPSC CAPF AC 2021 Paper

Let age of Raj be x yr
:. Age of Raj father's = 2x yr
Age of Raj grandfather's = 3x yr
According to the question,
Average age of Raj and his father = 45 yr
⇒

x+2x

2

= 45
⇒3x = 90
⇒ x = 30
Age of raj's grandfather = 3 × 30 = 90 yr