If you could fold a sheet of rice paper one thousandth 
of an inch thick exactly fifty times, how thick would 
the resulting wad be? 
 
 

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                  THE SOLUTION
 

Are you sitting comfortably?  The rice paper would be
17,769,885 miles thick.  If you don't believe it, try
folding it yourself.

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OK, let's check their answer.

After one fold the paper would be 2/1000 of an inch thick.
After two folds it would be 4/1000 of an inch thick.
After three folds it would be 8/1000 of an inch thick.
After four folds it would be 16/1000 of an inch thick.
Therefore,
after fifty folds it would be (2 to the power of 50)/1000 of an inch thick.
Converted to feet, it would be (2 to the power of 50)/(1000x12) feet.
Converted to miles, it would be (2 to the power of 50)/(1000x12x5280) feet.
Letting my TI-89 calculator crunch this calculation
   yields 1.77699 x 10 to the power of 7 which is the same as their answer.