Age of A is 10 years more than that of B. After T years, the average age of A and B will be T+25 years. Find the age (in years) of B after five years.

Correct option is C

Let the present age of A and B be a and b years respectively.
ATQ,
a – b = 10..(i)
And
a + T + b + T = 2T+50
a + b = 50…(ii)
From (i) & (ii)
a = 30, b=20
Required age = 20+5 = 25 years