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

`S_(26)=1300`

Step-by-step explanation

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

`S_(n)= (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)= (26)/(2) (7 + 93)`

`S_(26)= 13 (100)`

`S_(26)=1300`