After you graduated, you put the yearbooks you bought over the four years of HS on a bookshelf as in the figure: freshman yearbook, then sophomore, junior, and senior yearbooks. Each hardboard cover is 4 mm thick (4 mm each front and back), and the pages total 14 mm in thickness per yearbook. The yearbooks just sit there for quite a while until a bookworm starts chomping away on them. It begins on page 1 of the freshman yearbook and munches in a straight line until it reaches the last page of your senior yearbook. How many mm does it travel?
Solution
Visualize where page 1 of the freshman yearbook and the last page of the senior yearbook are located on the shelf. The bookworm eats through
millimeters. At least according to the problem (!), the worm does not eat any pages of the freshman or senior volume.