Say I have three objects A,B and C, each behind a door(door 1, 2, and 3). I don't know which object is behind which door. All permutations are equally likely so for every door, it has a 1/3 chance of holding each object. After certain events I can conclude that door 3 cannot hold object C. To get the new probabilities, I listed all permutations and eliminated those which door 3 holds object C, counted, and got the following:
Door 1: P(A) = 1/4, P(B) = 1/4, P(C) = 1/2
Door 2: P(A) = 1/4, P(B) = 1/4, P(C) = 1/2
Door 3: P(A) = 1/2, P(B) = 1/2, P(C) = 0
Is there a way to calculate the new probabilities by just looking at the current probabilities?