The average age of A and B is 20 years. If A is replaced by C, the average age becomes 19 years and if B id replaced by C, the average age becomes 21 years. Find the average ages A, B and C?

(a) 22, 18, 23                           (b) 20, 23, 21                      (c) 22, 18, 20              (d) 20, 18, 24

Average age of A and B = 20 years.

Average age of B and C = 19 years.

Average age of A and C = 21 years.

Sum of ages A and B = (20 ) years = 40 years.    …

Sum of ages Band C = (19 ) years = 38 years.     …

Sum of ages A and C = (21 ) years = 42 years.    …()

Adding  we get:

2 (sum of ages of A,B,C) = 120 years

?(sum of ages of A,B,C) = 60 years                             …

Subtracting  from , we get: C’s age  = 20 yrs.

Subtracting  from , we get: A’s age  = 22 yrs.

Subtracting  from , we get: B’s age  = 18 yrs.