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?

1 Answer
Feb 20, 2017

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!