The average age of three boys is 18 years and their ages are in the proportion 3 : 3 : 6. The age of the youngest boy is: Pick one:
A) 21 years B) 18 years C) 15.5 years D) 13.5 years E) None of these
Total age of 3 boys = (18 Ã— 3) years = 54 years. Ratio of their ages = 3 : 3 : 6.   Age of the youngest = (54 Ã— 3â„12) years = 13.5 years.   Answer 13.5 years
<result>D</result>
The average age of three boys is 18 years and their ages are in the proportion 3 : 3 : 6. The age of the youngest boy is: