Riya is 4 years older than her brother Kabir. The sum of their present ages is 28 years. How old is Kabir?

Explanation

1. 01

   Let Kabir's age be $x$; then Riya's age is $x + 4$.

2. 02

   $x + (x + 4) = 28$, so $2x = 24$.

3. 03

   $x = 12$, so Kabir is 12 and Riya is 16.