• + 1 comment

    super naively, I would say that the problem is just asking for the conditional probability of second marble being blue, given that the first is red, this is P(B = blue given A = red).

    When we have extracted the first red marble, the number of possible desired outcomes is 4 and the total possible outcomes is 6, so we arrive to the same solution.

    Does anybody knows if this result is the same just 'by chance'?