Find the average of first 18 natural numbers.  Choices:
A) 9.5
B) 19.5
C) 171
D) 18
E) 5.9
Explanation:   Sum of first n natural numbers = n(n+1)/2   Hence, sum of first 18 natural numbers = (18 x 19)/2 = 171   Therefore, required average of = 171/18= 
<gadget id="calculator">171/18</gadget>
<output>19/2 = around 9.5</output>
9.5   9.5NSWER: 9.5
<result>A</result>
Find the average of first 18 natural numbers.