Friday, December 1, 2023

**Problem:**

A square fence can be constructed by placing a number of posts in the ground next to each other so that they form a border around an interior space. In the example shown here, a square fence, five posts to a side, requires 16 posts.

Which formula will always calculate the number of fence posts needed for a square fence of sides `n`

× `n`

, where `n > 2`

?

`n * n - (n + 4)`

`n * 4 - (n - 1)`

`n * 4 - 4`

- I only
- II only
- III only
- I and II only
- I and III only

See the solution here.

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