A26-volume encyclopedia(1 volume for each letter) is placed on a bookshelf in alphabetical order from left to right. each volume is 2 inches thick, including front and back covers. each cover is 1/4 inch thick. a bookworm eats straight through the encyclopedia , beginning inside the front cover of volume a and ending after eating through the back cover of volume z. how many inches of book did the bookworm eat?

Eating from the inside cover of the first book to the back cover of the last boook, will take the bookworm 25 full books (that is from B to Z) and for book A, the total distance should be subtracted by 1/4 (that is the length of the inside cover)
                          total distance covered = (2)(25) + (2 - 1/4)
The answer to the equation above is,
                           total distance covered = 51.75 inches