The average age of 6 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) 30years
Total age of 6 boys = 25*6= 
<gadget id="calculator">25*6</gadget>
<output>150</output>
150   ratio of their ages= 3:5:7   Age of the youngest = 150*3/15= 
<gadget id="calculator">150*3/15</gadget>
<output>30</output>
30 years   Answer is 30years
<result>E</result>
The average age of 6 boys is 25 years and their ages are in the proportion 3:5:7. The age of the youngest boy is?