The average age of three boys is 20 years and their ages are in proportion 3:5:7. What is the age in years of the youngest boy? Choose the correct answer
A) 6	B) 9	C) 8	D) 4	E) 12
3x + 5x + 7x = 60   x =4   3x = 12   Answer:12
<result>E</result>
The average age of three boys is 20 years and their ages are in proportion 3:5:7. What is the age in years of the youngest boy?