Delhi Police Constable Exam Model Paper 3

Tips & Tricks
Let ‘a’ be Rohit’s son’s present age.
Rohit was 4 times as old as his son 8 years ago.
Rohit’s age = 4(a – 8)After 8 years, Rohit will be twice as old as his son.
Rohit’s age = 2(a + 8)
According to question:
$2\left(\mathit{a}+8\right)-4\left(\mathit{a}-8\right)=16$
∴ $2\mathit{a}+16-4\mathit{a}+32=16$
∴ $-2\mathit{a}+48=16$
∴ $-2\mathit{a}=16-48$
∴ $-2\mathit{a}=-32$
∴ $\mathit{a}=16$
After 8 years, Rohit’s age = 2(a + 8)
So, present age of Rohit = 2(a + 8) - 8
= 2(16 + 8) - 8
= 2(24) - 8
= 48 - 8
= 40
Hence, Rohit’s present age is 40 years