Question 213056: A grocer makes a display of cans in which the top row has one can and each lower row has two more cans than the last row. If the display has 100 cans, how many rows does it contain?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A grocer makes a display of cans in which the top row has one can and each lower row has two more cans than the last row. If the display has 100 cans, how many rows does it contain?
------------------------------------
It's an arithmetic sequence: 1,3,5,7,...,2n-1
----------------
S(n) = (n/2)(1 + 2n-1] = 100
n[1 + 2n-1] = 200
---
n[2n] = 200
2n^2 = 200
n^2 = 100
n = 10 (# of rows)
==========================
Cheers,
Stan H.
|
|
|
