Four cousins have an average age of 26 years. Three of them are 23, 24 and 27. How old is the fourth?

A) 31 years

B) 30 years

C) 29 years

D) 32 years

Answer: B

Explanation: The combined age is average × four; subtract the three given ages.
Fourth age = 4 × 26 − 23 − 24 − 27 = 30 years.