SOLUTION: Find the sum. 5+10+15+...+430 a.) 18,275 b.) 18,705 c.) 37845/2 d.) 18,490

Algebra ->  Sequences-and-series -> SOLUTION: Find the sum. 5+10+15+...+430 a.) 18,275 b.) 18,705 c.) 37845/2 d.) 18,490      Log On


   

Question 1059610: Find the sum. 5+10+15+...+430
a.) 18,275
b.) 18,705
c.) 37845/2
d.) 18,490
Answer by ikleyn(52914) About Me  (Show Source):
You can put this solution on YOUR website!
.
5 + 10 + 15 + . . . + 430 = 5*(1 + 2 + 3 + . . . + 86) = 5%2A%28n%2A%28n%2B1%29%29%2F2 = 5%2A%2886%2A87%29%2F2 = 18705.

Option b).

For introductory lessons on arithmetic progressions, see
    - Arithmetic progressions
    - The proofs of the formulas for arithmetic progressions
    - Problems on arithmetic progressions
    - Word 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".