The average age of 15 students of a class is 15 years. Out of these, the average age of 5 students is 12 years and that of the other 9 students is 16 years. The age of the 15th student is? Choices:
A) 11 years
B) 17 years
C) 21 years
D) 14 years
E) 12 years
Age of the 15th student   =[15 * 15 - (12 * 5 + 16 * 9)]   = (225 - 204)= 
<gadget id="calculator">(225 - 204)</gadget>
<output>21</output>
21 years.   Answer:21 years
<result>C</result>
The average age of 15 students of a class is 15 years. Out of these, the average age of 5 students is 12 years and that of the other 9 students is 16 years. The age of the 15th student is?