Question

Can someone please help me with this?

Answer 1

`S_(13)` = 403

Explanation:

the sum to n terms of an arithmetic series is

`S_(n)` =
`(n)/(2)` (a + l) ← a is the first term and l the last term

here a = - 5 and l = 67 , then

`S_(13)` =
`(13)/(2)` (- 5 + 67) = 6.5 × 62 = 403