the average age of 3 boys is 120 years and their ages are in proportion 2 : 6 : 8 . what is the age in years of the youngest boy ? Select.
A) 10 B) 9 C) 15 D) 6 E) 12

Rationale: 2 x + 6 x + 8 x = 120 x = 7.5 2 x = 15 answer : c
Answer: C