# How many possible codes are there if the digits cannot be repeated? How many possible codes are there if the digits cannot be repeated?

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A Store-It-All storage facility requires users to enter a four digit code, using numbers 0-9, to get through the gate. You need to get a box of winter clothes from your storage container, but you forgot the code.

How many possible codes are there if the digits cannot be repeated?

What is the probability that you will guess the correct code on your first try?

P(correct code) = **_**_

A Store-It-All storage facility requires users to enter a four digit code, using numbers 0-9, to get through the gate. You need to get a box of winter clothes from your storage container, but you forgot the code.

How many possible codes are there if the digits cannot be repeated?

What is the probability that you will guess the correct code on your first try?

P(correct code) = **_**_

##### 1 Answer

Jun 27, 2018

You have 10 different digits for the first place (that is, if 0 is allowed), when that is chosen, you have 9 left and so on, i.e.

Each of these codes has the same probability to be chosen if they are chosen totally randomly. Therefore

P(correct code)=