SSC CHSL Model Paper 10

Let Varun's age today = x years
Then, Varun's age after 1 year = (x + 1) years
And, Varun’s age before 12 years = (x – 12) years
Therefore, (x + 1) = 2(x – 12)
⇒ x + 1 = 2x – 24 ⇒ x = 25