SOLUTION: How do you find the sum of the finite arithmetic series of 9, 16, 23, 30, ..., 100? Thank you

Question 178522: How do you find the sum of the finite arithmetic series of 9, 16, 23, 30, ..., 100?
Thank you
Answer by Mathtut(3670) (Show Source): You can put this solution on YOUR website!
I think I finally figured this one out.
:
9 is added to each progressive term and 7's increased by the summation of the number of terms in the sequence The 7's part of this sequence is just a play on Gauss's summation formula.
:
so
:
9(n+1)+7n(n+1)/2. n is the number of terms . You can figure the number of terms by dividing whatever the number of the last term is and subtracting 9 ,then dividing by 7....such as 100 is the last term so subtract 9 and divide by 7...answer is 13......so n would equal 13
:
9(13+1)+7(13)(14)/2=126+637=
:
you can rewrite the formula to
:
(n+1)(9+(7n/2))=

RELATED QUESTIONS
What is the sum of the finite arithmetic... (answered by ewatrrr)

find the sum of infinite geometric series -16+12-9+... Thank you! (answered by jim_thompson5910)

for part (a) find the sum of the first n terms of the arithmetic series. for part (b)... (answered by mathstutor458,KMST)

the sum of the finite arithmetic series 2+4+6+8...+70 is (answered by LinnW)

How do you find the sum of infinite geometric... (answered by stanbon)

Worksheet from my school OHVA Find the sum of the arithmetic series 1+14+27+...+183 (answered by arallie)

The last three terms of an arithmetic sequence with 18 terms is as follows: 67,72,77. How (answered by ikleyn)

Consider the arithmetic series 2+9+16+... . Find the number of terms that will give a... (answered by chen.aavaz)

I hope you can help sove this question; The first term in an arithmetic series is 16... (answered by vleith)