Basic Math/math


Dear John:

I write mystery novels - I'm working on a scene involving a combination safe - a 3 number combination - safe dial from 0 to 99, and would like to know the number of possible combinations available.

Sincere thanks for your time.

Jerry Kennealy

Hello, Jerry.

That's interesting. I have also written books. I wish you the best!

(I'm sorry, but my previous answer (if you received it) was incorrect. I forgot to take the 0 on the safe dial into account.)

If the numbers may be repeated: 100 x 100 x 100, or 1,000,000 different safe combinations.

If the numbers may not be repeated: 100 x 99 x 98, or 970,200 different safe combinations.

Hope this helps.


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John Zalewski


I can help you solve problems involving fractions, decimals, ratios, and algebra. I can teach you how to do math faster, and even in your head. I can teach math definitions, and help you study, if necessary. Please do not ask any graphing, trigonometry, or calculus questions. Try to work through homework questions before asking for assistance.


I routinely process numbers of all kinds in my head, without need of a calculator.

I was an A math student while in high school.

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