A bookworm eats from the first page of encyclopaedia number 1 to the last page of encyclopaedia number 5. The bookworm eats in a straight line. Each encyclopaedia consists of 400 pages. Each leaf is 0.01 inch thick and each cover is 0.25 inch thick. What distance does the bookworm eat through?
Answer
The bookworm nibbles its way through approximately eight inches. The first page of the first volume is the rightmost page of the first
volume. The last page of the last volume is the leftmost page of the last volume. So the only part of the first volume it eats is the front cover, and the only part of the last volume it eats is the back cover.
The reason the answer is not fourteen inches is that while each leaf is .01 inch thick, each leaf is two pages. So, 400 pages is only two inches thick.
Finally, we say approximately eight inches because it is a matter of semantics whether the bookworm ate the first page of the first volume.
