SOLUTION: A computer program password is made up of 3 digits chosen randomly . Find the probability of getting each password as follows. 3 prime digits and the digits cannot be repeated.

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Question 955317: A computer program password is made up of 3 digits chosen randomly . Find the probability of getting each password as follows. 3 prime digits and the digits cannot be repeated.
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
prime digits between 0 and 9 are:

2, 3, 5, 7

that's 4 out of 10.

probability of a digit being a prime is therefore equal to 4/10

the probability of all 3 digits being prime if the digits can be repeated is therefore equal to 4/10 * 4/10 * 4/10 which is equal to 64 / 1000.

if the digits can't be repeated, then the probability is 4/10 * 3/9 * 2/8 which is equal to 24 / 720.