Pat has two sheets of large, square stamps. One sheet consists of 9 stamps arranged in a 3-by-3 square. (That's 3 stamps by 3 stamps, not 3 inches by 3 inches.) The other sheet consists of 36 stamps arranged in a 6-by-6 square. The stamps on each sheet are separated by perforated creases. All the stamps on both sheets are the same shape and size.
The total length of the creases on the 3-by-3 sheet is 18 inches.
How many inches of creases does the 16-by-16 sheet have?
here are 4 lines on the 3 x 3 page encompassing 12 borders .... 18 / 12 = 1.5 inch side length of stamp
the 6 x 6 will have 10 lines each covering 6 edges 6 edges x 1.5 inches x 10 = 90 inches