A bookworm can chew through a millimiter (mm) of paper or cardboard in half an hour. One day it encounters a particularly tasty treat: a two-volume edition of a large book standing on a shelf as shown.

The volumes are identical in size, each has a front and a back cover that is a millimeter thick on each side, and the pages of each are a 10mm thick stack of paper from the first page to the last.

If a bookworm starts its meal on the first page of the first volume (already inside the front cover), how long will it take to eat his way through to the last page of the second volume (inside the second volume’s back cover)?

Bookworm needs to eat through frontcover of book 1 and back cover of book 2 = 1 mm + 1mm = 2 mm

 

So it will take 1 hour

 

Think of the orientation of the books ...

Posted by cyclothymic on 2008-06-27 16:26:49