SOLUTION: A stack of poles has 70 poles in the bottom row, 68 poles in the next row, and so on, with 6 poles in the top row. How many poles are there in the stack?

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: A stack of poles has 70 poles in the bottom row, 68 poles in the next row, and so on, with 6 poles in the top row. How many poles are there in the stack?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1104821: A stack of poles has 70 poles in the bottom row, 68 poles in the next row, and so on, with 6 poles in the top row. How many poles are there in the stack?
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
70-2%28n-1%29, the general term for arithmetic sequence


70-2%28n-1%29=6
Solve for n, the number of rows

70-2n%2B2=6
72-6=2n
2n=66
n=33


Total of poles in ALL the rows?
%2833%2F2%29%2870%2B6%29-----based on formula for sum of arithmetic sequence
33%2835%2B3%29
highlight%281254%29

Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.
See the lesson
    - Word problems on arithmetic progressions
in this site.

---------------
There is a bunch of lessons on arithmetic progressions in this site
    - Arithmetic progressions
    - The proofs of the formulas for arithmetic progressions
    - Problems on arithmetic progressions
    - Word problems on arithmetic progressions
    - Chocolate bars and arithmetic progressions
    - Mathematical induction and arithmetic progressions
    - One characteristic property of arithmetic progressions
    - Solved problems on arithmetic progressions


Also, you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic
"Arithmetic progressions".