Laila is four years older than his two-year-old brother Mansoor. How old will Mansoor be when he is half the age of his older sister Laila?

A) 2

B) 4

C) 6

D) 8

Leila brother age = 2 

              Leila age = 8

After passing X years Mansoor will half of its sister age so

2 + X = 1/2( 8 + X) 

4 + X = 8 + X

⇒   X = 4

So Mansoor will half of his sister age after 4 years.