The average age of three boys is 15 years and their ages are in proportion 3:5:7. What is the age in years of the youngest boy?  Answers.
A) 9 B) 10 C) 11 D) 12 E) 13
Explanation:   3x + 5x + 7x = 45   x =3   3x = 9   9)
<result>A</result>
The average age of three boys is 15 years and their ages are in proportion 3:5:7. What is the age in years of the youngest boy?