if posts are spaced 13 feet apart how many posts are needed

if posts are spaced 13 feet apart, how many posts are needed for 143 feet of staight line fence?

Solution

Note that

#posts = [length of fence / spacing of posts] + 1

Thus, as length of fence = 143 ft, spacing of posts = 13 ft, then

#posts = 143/13 + 1

= 12 posts [ANSWER]