The average age of A, B and C is 26 years. If the average age of A and C is 29 years, what is the age of B in years ?
Select.
A) 19  B) 35  C) 20  D) 32  E) 21

Rationale: "c 20 age of b = age of ( a + b + c ) – age of ( a + c ) = 26 × 3 – 29 × 2 = 78 – 58 = 20 years"
Answer: C