Question

If I have a 20 sided dice and roll it twice, what are the odds that I will roll the same number twice?

Answer 1

It depends on the condition... Perhaps `1/20` is more suitable.

Explanation:

In this situation, the probability of getting the `color(red)"given"` number twice, for example, rolling a `1` twice, will be `1/20*1/20=1/400.`

However, the probability of rolling `color(blue)"freely selected"` number twice, i.e. any of two 1s, two 2s, ...two 20s, will be `1/400*20=1/20`.