The average age of 20 students of a class is 20 years. Out of these, the average age of 9 students is 11 years and that of the other 10 students is 24 years. The age of the 20th student is?
Choose the correct answer:
A) 65
B) 61
C) 59
D) 63
E) 64
Age of the 20th student = 20*20 - (9*11+10*24) = 400-339= 
<gadget id="calculator">400-339</gadget>
<output>61</output>
61 years   Answer is 61
<result>B</result>
The average age of 20 students of a class is 20 years. Out of these, the average age of 9 students is 11 years and that of the other 10 students is 24 years. The age of the 20th student is?