## anonymous 4 years ago What is the sum of the arithmetic sequence 8, 14, 20 …, if there are 24 terms?

1. anonymous

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.

2. anonymous

sorry, it should be: S = n/2( 2a + (n-1)d)

3. Mertsj

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

4. Mertsj

There. I think I finally got it right.

5. anonymous

THANK YOU

6. Mertsj

yw

7. anonymous

|dw:1328989953105:dw|

8. anonymous

1848

9. anonymous

you put a1=6 but it is 8

10. anonymous

|dw:1328990276982:dw|

11. anonymous

The correct answer is 1848! Tyy!!