Monday

December 22, 2014

December 22, 2014

Posted by **Schuyler** on Monday, June 20, 2011 at 10:02am.

- Alg 2 -
**Raymond**, Monday, June 20, 2011 at 10:27amSchuyler, the sum of the 12 term aritmetic progression is 816

- Alg 2 -
**Raymond**, Monday, June 20, 2011 at 11:17amSchuyler, in order to solve your problem I had to turn it around (Gloria Estefan?). You said the last term was 13...I made it the first term. You said the common difference was a -10...I made it a +10.

Now I had to find the last term so I used this formula: L=a+(n-1)d so 13+(12-1)10

L=123

Then I used this formula:

Sn=n/2(a+L)

Sn=12/2(13+123)

Sn=6 Times 136

Sn=816

**Answer this Question**

**Related Questions**

Algebra - True or False 1. – 5, – 5, – 5, – 5, – 5, … is an arithmetic sequence...

Maths - 1..The first 2 terms of a geometric progression are the same as the ...

Arithmetic Sequence - Given the third term of an arithmetic sequence less than ...

Precalculus - The 8th term in an arithmetic sequence is 5, and the sum of the ...

math - find the rule for the Nth term of the arithmetic sequence. 11/2, 25/6, 17...

math - The 3rd term in an arithmetic sequence is 12, the 7th term is 24, a) How...

Mathematics : Arithmetic Sequence - The 5th term and the 8th term of an ...

Math - A sequence is formed by adding together the corresponding terms of a ...

math - What is the sum of a 12–term arithmetic sequence where the last term is ...

math - What is the common difference of a 43–term arithmetic sequence where the ...