math
posted by coach on .
A rectangle measures 30 feet by 20 feet and has a post at each corner. If posts are placed 2 feet apart. How many posts will there be in all?

You would need 34 posts. I drew this out and then added up each post. Note that some of the posts will be less than two feet apart because there has to be a post on each corner.

Ignoring the corner posts, there are 14 posts along each long side, 9 posts along each short side and the 4 corner posts for a total of 2(14) + 2(9) + 4 = 50