Answers to Contest Center puzzles, riddles and brainteasers

Riddle Answers
The Contest Center
59 DeGarmo Hills Road
Wappingers Falls, NY 12590
Pan Balance
       Many people immediately jump to the answer that you should buy weights of 1, 2, 4, 8, 16, etc. ounces. This is because they learned in school that these can be added to make any whole number, for example 21 is 16+4+1. So you could weigh a 21-ounce object by putting it in one pan, and placing weights 1, 4 and 16 in the other pan.
       People who consider the problem more carefully will realize that you can put the weights on either pan. Using weights 1, 3, 9, 27, 81, etc. you can add and subtract them to make any whole number, for example 21 is 27+3-9. So you could weigh a 21-ounce object by placing it in one pan along with the 9-ounce weight, and putting 3 and 27 in the other pan.




The Contest Center welcomes contributions of your original puzzles, riddles and jokes, including anagrams, cryptograms, plus math-themed art and animations. Share your creations with other puzzle-lovers.

All submissions must be your own original work. Do not submit material that is copyrighted elsewhere. Do not submit material that you found in books, magazines, TV shows, movies, podcasts, or on other websites.

Send submissions to Contest Center Submissions
Submit puzzle answers to Contest Center Answers
Send questions and correspondence to Contest Center Mail

Quick Links
HOME SITE MAP


© Copyright 2025 The Contest Center