UPSC 2017 CDS I Math Paper

Let the present age of her son be x years.
Therefore, present age of Leela = 10x years
Present age of Leela =1

1

4

×Age of Leela's 6 years ago
∴10x=

5

4

(10x−6)
⇒8x=10x−6
⇒2x=6
⇒x=3
Thus, the present age of her son is3 years.