Question

Consider the sequence $1,-2,3,-4,5,-6,..........,n$ $(-1{)}^{n+1}.$ What is the average of the first $300$ terms of the sequence ?

• A. $-1$
• B. $0.5$
• C. $0$
• D. $-0.5$

Answer 1

The correct option is D $-0.5$

Here sum of 1 pair is -1, and there are 150 pairs so, sum will be -150

Average= Sum of all the numbers/total no

Av=-150/300=-0.5

Answer (D) -0.5