Answer
$15, 960$
Work Step by Step
We can see that there are $120$ terms and these terms are part of an arithmetic sequence, so we have: $a_1=14$
There is a constant difference between the terms of: $d=2$
The sum of the first $n$ terms of an arithmetic sequence is given by:
$S_{n}= \dfrac{n}{2}\left(a_{1}+a_{n}\right) ..(1)$
Now, we plug in the above data into Equation-1 to obtain:
$S_{120}= \dfrac{120}{2}[(2)(14)+(2)(120-1)] \\=(60)(226) \\= 15, 960$
Therefore, the sum of the arithmetic sequence is: $15, 960$.
