Originally Posted by DAD22
Originally Posted by ec_bb
Kevin is using wooden rods to make picture frames. The length and width of one picture frame and the length of one wooden rod are shown below:

(diagram of a rectangle with dimensions of 10 inches and 8 inches marked, and a single wooden rod marked with a length of 48 inches)

1) What is the perimeter, inches, of the picture frame?
(straight forward -- no complaints there)

2) How many wooden rods does Kevin need if he makes 4 picture frames like the one above?

Well, the only answer they gave credit for was 3 -- perimeter x 4 divided by 48.

I wonder how many kids did the calculation you explained to arrive at 3, and how many checked to see whether or not you could actually cut 8 10" pieces and 8 8" pieces from 3 48" rods. It turns out you can (if you ignore losses due to the width of your saw blade and sanding... which would require you to use 4 rods in the real world). At least the question authors got that much right.

I didn't worry about sanding or cut width, because in the real world, you wouldn't. This is a picture frame, not a sensitive scientific instrument. And if we assume that this is being done by a skilled worker with high-quality tools, the losses should be near enough to constant so that we still end up with a rectangle.

It's that waste at the end that I see as a problem in the real world. If you cut out the lengths you need, you'll have enough wood, but one side of one frame will consist of three waste pieces glued together. It's hideous and unprofessional.