Question

Elijah forgot his pass code for a certain website. He knows it is made up of 5 digits and no digit can be repeated. If he randomly chooses 5 different digits, what is the probability that he chooses his pass code?

Answer 1

The chances are `1/(30,240)`.

Explanation:

Use the permutation formula, as order matters, to determine the number of permutations that are possible. Call the number of permutations `P`. There are 10 possible digits to choose from, and he needs to choose `5` different digits, so `P` is given by

`P = (n!)/((n - r)!)`

`P = (10!)/((10 - 5)!)`

`P = 30240`

If he randomly chooses one set of `5` digits, than his chances that he chooses the correct pass code is `1/(30,240)`

Hopefully this helps!