SEED Science

Balancing the Books

Math Puzzles of the Month
Balancing the Books

Thanks to David Tempel for suggesting this puzzle, which asks how big a stack can you make before it goes over the edge.

Book over edge
 
Books over edge
 

 

 You can put a book on a table with part of it over the edge. As long as enough of the book is on the table, it will not fall. How much is "enough"? Just the tiniest bit more than half.

Now we can pile two books on the table so that the top one extends over the edge by more than half its length.

Is it possible to stack more books in this fashion so that the top one is fully beyond the edge of the table? If it is possible, how many books do you need?

First take a guess. Then try it. And finally, give an explanation of your result.

After you've tried this for yourself, check our solution.


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