Find the average of first 20 natural numbers?  Select.
A) 5.5	B) 7.2	C) 10.5	D) 12.3	E) 15.5
Sum of first n natural numbers = n(n+1)/2   sum of first 20 natural numbers = 20*21/2= 
<gadget id="calculator">20*21/2</gadget>
<output>210</output>
210   average= 210/20= 
<gadget id="calculator">210/20</gadget>
<output>21/2 = around 10.5</output>
10.5   Answer is 10.5
<result>C</result>
Find the average of first 20 natural numbers?