Rolling an 8-sided die, after 5 rolls, what is the probability of at least 1 number being rolled twice?

1 Answer
Mar 29, 2018

The probability of at least one number appearing twice in five rolls is 407/512407512.

Explanation:

The probability of no number occurring twice after five rolls is 8/8*7/8*6/8*5/8*4/8 = 105/5128878685848=105512.

To get the probability of at least one number occurring twice, subtract the above probability from 11:
1-105/512 =407/5121105512=407512