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Physical Sciences and Mathematics Commons

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Discrete Mathematics and Combinatorics

Claremont Colleges

Series

1996

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Full-Text Articles in Physical Sciences and Mathematics

Combinatorics And Campus Security, Arthur T. Benjamin Jan 1996

Combinatorics And Campus Security, Arthur T. Benjamin

All HMC Faculty Publications and Research

One day I received electronic mail from our director of campus security [Gilbraith 1993]:

"I have a puzzle for you that has practical applications for me. I need to know how many different combinations there are for our combination locks. A lock has 5 buttons. In setting the combination you can use only 1button or as many as 5. Buttons may be pressed simultaneously and / or successively, but the same button cannot be used more than once in the same combination.

I had a student (obviously not a math major) email me that there are only 120 possibilities, but …