Question

Assuming the pattern continues, what is S12 for the series−8 − 15 − 22 − 29 − …? −565 −85 −510 −558

Answer 1

Notice that:

`\begin{gathered} -8=-1-7*1, \\ -15=-1-7*2, \\ -22=-1-7*3, \\ -29=-1-7*4. \end{gathered}`

Therefore, the nth term of the given sequence is given by the following rule:

`S_n=-1-7* n\text{.}`

Then:

`S_(12)=-1-7*12=-1-84=-85.`

Answer: Second option.