We have an urn with 40 balls of those 12 are white 11 are red and 17 are green. We extract 6 of them. We must find the probability that 3 are white 2 are red and 1 is green.
The solution should be 0,054
I'm struggling with these arguments and I didn't find some clear explanations about them,as far as I've understood we shouldn't use combinatorics when we don't have equiprobable spaces, which should be the case of this example since every color has a different probability to be extracted. Searching on the web (in italian) I've seen similar examples that use combinatorics, I've tried to apply those solutions for my problem but none of them gave me the expected result, what am I missing?