Question

Question 8 of 14

2 Points
What is the sum of the arithmetic series of odd numbers below?
1+ 3 + 5 + ... + 23


APEX!!!

Answer 1

276 is correct

Answer 2

144.

Explanation:

Sum of n terms = (n/2)[a1 + l] where a1 = first and l = last term.

There are ( 1 + 23) / 2 = 12 terms in this series.

So the sum = (12/2) [ 1 + 23]

= 6 * 24

= 144.