1.  Three years ago, the average age of A and B was 18 years. With C joining them, the average age become 22 years. How old is C now ?
A. 24 years
B. 27 years
C. 28 years
D. 30 years

Answer: Option A

Explanation:

Present age of (A + B)
= (18 x 2 + 3 x 2) years
= 42 years.

Present age of (A + B + C)
= (22 x 3) years = 66 years.

C's age = (66 - 42) years = 24 years.