The average age of 3 girls is 18 years and their ages are in the proportion 1:2:3. The age of the youngest girl is? Choose the correct option:  A) 10 years  B) 9 years  C) 12 years  D) 14 years  E) 15 years
Total age of 3 boys = 18*3= 
<gadget id="calculator">18*3</gadget>
<output>54</output>
54   ratio of their ages= 1:2:3   Age of the youngest = 54*1/6= 
<gadget id="calculator">54*1/6</gadget>
<output>9</output>
9 years   Answer is 9 years
<result>B</result>
The average age of 3 girls is 18 years and their ages are in the proportion 1:2:3. The age of the youngest girl is?