Question

Time sensitive question. Find the sum of the first 26 terms of an arithmetic series whose first term is 7 and 26th term is 93.

Answer 1

ANSWER

$S_{26}=1300$

EXPLANATION

The sum of an arithmetic sequence whose first term and last terms are known is calculated using

$S_{n}= \frac{n}{2} (a + l)$

From the given information, the first term of the series is

$a = 7$

and the last term of the series is

$l = 93$

The sum of the first 26 terms is

$S_{26}= \frac{26}{2} (7 + 93)$

$S_{26}= 13 (100)$

$S_{26}=1300$