Two volumes of William Shakespeare stand on a bookshelf next to each other: volume one, then volume two. Each volume is 4 cm thick (pages + two covers), and has two covers, each 0.5 cm thick. A bookworm starts on page 1 of volume one and munches his way in a straight horizontal line through to the last page of volume two. What distance does the worm travel?

L = 7 [cm]

Explanation:

To solve this problem we must analyze each of the distances mentioned and take into account the number of covers and thicknesses of these.

The worm crosses through the sheets of the first book, this distance can be determined by the following length analysis.

4 = P + 2*C

Where:

P = thicknesses of the pages [cm]

C = thicknesses of each cover [cm]

P = 4 - 2*(0.5)

P = 3 [cm]

The distance crossed was:

L = P + 2C + P "the pages of the first book + 2 covers + the pages of the second book"

L = 3 + (2*0.5) + 3

L = 7 [cm]

the first, second, and fifth options