1. BOOKWORM BATTLE
US VERSION

2. The Bookworm
You have a full encyclopedia consisting of 20 books with topics from A to Z. Each book consists of a cover, which is a half an inch thick. Each book has pages, which in total are 2 inches thick. A bookworm jumps into the first page in the first encyclopedia, the one starting with A. The worm eats its way through the first encyclopedia, 2 more and finishes at the last page of the forth. How many inches the bookworm eat through?

3. Solution
The bookwork actually starts at the cover of the first book (but only half a cover): ¼ inch. It eats through 2 full books including 2 full covers: ¼ inch + 2 inches + ¼ inch + ¼ inch + 2 inches + ¼ inch. Then through half a cover ending up at the last page of the fourth: ¼ inch. So, in total, the bookworm eats: ¼ + ¼ 2 + ¼ + ¼ ¼ + ¼ totaling 5 1/2 inches of book.

5. BOOKWORM BATTLE
EUROPEAN VERSION

6. The Bookworm
You have a full encyclopedia consisting of 20 books with topics from A to Z. Each book consists of a cover, which is 1 cm thick. Each book has pages, which in total are 5 cm thick. A bookworm jumps into the first page in the first encyclopedia, the one starting with A. The worm eats its way through the first encyclopedia, 2 more and finishes at the last page of the forth. How many centimeters the bookworm eat?

7. Solution
The bookwork actually starts at the cover of the first book (but only half a cover): ½ cm. It eats through 2 full books + covers: 5 cm + 1cm + 5 cm + 1 cm Then through half a cover ending up at the last page of the fourth: ½ cm. So in total, the bookworm eats: ½ + ½ ½ + ½ ½ + ½ totaling 13 cm of book.