ANSWER
1199
EXPLANATION
The given series is

To find the first term of this series, we put n=9 into the formula.

To find the last term, we put n=30

There are 22 terms from the 9th term to the 30th term
The sum of the consecutive n-terms of an arithmetic series is given by;

We substitute n=22, a=23, and l=86 to get;


