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## Homework Statement

A password has numbers 0-9 in it. The password is 5 digits, repeats are not allowed, and order doesn't matter (I just have to have the correct 5 digit buttons depressed).

A. If I guess at the password, what is the probability that the box will open?

B. If I have completely forgotten the password, what is the probability that it will take less than 10 tries to get it open?

Show your work and/or explain your process.

## Homework Equations

Combination

## The Attempt at a Solution

10C5 = 252

1/252 = .003 The chances of guessing the code (This seems to low how the order doesn't matter of the numbers as long as they are pushed right)

(1/252)+(1/251)+(1/250)....(1/1/242) =.04% (Also seems to low)

I thought maybe I need to do 5x10/252 because order doesn't matter and there 5 digits and 10 numbers to choose from.

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