Packing It In

During the holidays, people tend to mail large boxes to relatives and friends.  If you are not careful, you may end up going to the post office, only to find out that the box you have packed and taped is too large.

According to the US Post Office guidelines, the sum of a package's length and girth (distance around its midsection) can not exceed 108 inches.  The formula for computing package size is 

1. Can you mail a 24"x24"x48" (Width by Height by Length) package?
2. What is the maximum length of a package that is 26" wide by 20" tall?
3. Many boxes have equal width and height.  How would you adapt the formula?
4. Use the formula you just created to find the maximum width/height for a 60" package.
5. Rewrite the formula if the box is a cube.
6. What is the maximum dimensions of a cubic box to be shipped?