The average age of three boys is 15 years. If their ages are in the ratio 3:5:7, the age of the youngest boy is :
Choose the correct choice:
A) 9  B) 8  C) 7  D) 6  E) 5
Explanation:   3x+5x+7x3=15⇒15x=15×33x+5x+7x3=15⇒15x=15×3 or x = 3   9ge of youngest = 3x = 9 years   9nswer:\9
<result>A</result>
The average age of three boys is 15 years. If their ages are in the ratio 3:5:7, the age of the youngest boy is :