The average age of 3 boys is 15 years and their ages are in the proportion 1:2:3. The age of the youngest boy is?
Pick one:
A) 10 years
B) 12 years
C) 15 years
D) 18 years
E) 7.5 years
Total age of 3 boys = 15*3= 
<gadget id="calculator">15*3</gadget>
<output>45</output>
45   ratio of their ages= 1:2:3   Age of the youngest = 45*1/6= 
<gadget id="calculator">45*1/6</gadget>
<output>15/2 = around 7.5</output>
7.5 years   Answer is 7.5 years
<result>E</result>
The average age of 3 boys is 15 years and their ages are in the proportion 1:2:3. The age of the youngest boy is?