Posted by **Abbey(Please help)** on Tuesday, May 4, 2010 at 4:37pm.

Logs are stacked up in apile as shown in the figure. The top row has 15 logs and the bottom row has 21 logs. How many logs are in the stack?

a1= 1+14=15

an= 7+14=21

s1=(n/2)(a1+an)

(n/2)(15+21) = 18

How do I figure out the n?

- Math -
**Abbey(Please help)**, Tuesday, May 4, 2010 at 4:39pm
Would n be 14?

- Math -
**Reiny**, Tuesday, May 4, 2010 at 4:45pm
n/2(26) = 18

26n = 36

n = 36/26

something very wrong with your equation, since n has to a whole number

where does the 18 come from?

you seem to be using the formula

S(n) = n/2(first + last)

so 18 would be the sum of the logs ????

that makes no sense, since the bottom row alone contains 21 logs.

## Answer This Question

## Related Questions

- algebra - 200 logs are stacked so that 20 logs at bottom row 19 in the next ,18...
- math - natural logs - Find the EXACT solution to e^(1-x) = 4^x You must use logs...
- math logs - solve 3^(2x+1) = 9^(2x-1) using base 3 logs
- Precalculus - .5=e^(-20t) I am assuming this involves logs but we did't really ...
- Maths (Logs) - 1.Write the following equation without logs log y = mx+ c This ...
- Pre Cal (logs) - I need help with these logs 1: Log underscore4 16X 2: 2 Ln ( X(...
- Math - Could you check these pleas? Firewood usually sold by a measure known as ...
- chem - "Yule logs are simulated wood logs make of compressed paper that burn ...
- Math (check please) - Could you check these please? Firewood is usually sold by...
- math - bricks are stacked in 20 rows such that each row has a fixed number of ...

More Related Questions