Question

What is the sum of the arithmetic sequence 8, 14, 20 …, if there are 24 terms?

Answer 1

S = 2a + (n-1)d

Where a = first number in sequence, n is nth term you are looking for and d is the common difference.

Answer 2

sorry, it should be:

S = n/2( 2a + (n-1)d)

Answer 3

\[s _{n}=\frac{n}{2}(a _{1}+a _{n})\]
To find the 24th term use:
\[a _{n}=a _{1}+(n-1)d=8+(24-1)6=146\]
\[s _{n}=\frac{24}{2}(6+146)\]
\[s _{n}=1824\]

Answer 4

There. I think I finally got it right.

Answer 5

THANK YOU

Answer 6

yw