The average age of 3 boys is 25 years and their ages are in the proportion 3:5:7. The age of the youngest boy is?	Choose the correct choice from the following answers: A) 10years B) 15years C) 20years D) 25years E) 18years
Total age of 3 boys = 25*3= 
<gadget id="calculator">25*3</gadget>
<output>75</output>
75   ratio of their ages= 3:5:7   Age of the youngest = 75*3/15= 
<gadget id="calculator">75*3/15</gadget>
<output>15</output>
15 years   Answer is 15years
<result>B</result>
The average age of 3 boys is 25 years and their ages are in the proportion 3:5:7. The age of the youngest boy is?