Answer:
a. 18
Step-by-step explanation:
AB+BC = AC
x + x = 36
2x = 36
x = 36/2
x = 18
Let's the name the first number x and the consecutive number x + 1. The sum of both of these numbers equals to 53.
We now have our equation:
x + x + 1 = 53
Now solve for x.
x + x + 1 = 53
2x + 1 = 53 <-- Combine like terms
2x = 52 <-- Subtract 1 from each side
x = 26
So, the first number is 26 and the second number is 27.
The terms in the sum are given by the sequence

We have

for all
, and the series
clearly diverges, so
must also diverge.