Can anyone help me with my question????
There are two boxes each containing some black and white balls. In box A, the number of white cards is three times that of black cards. In box B, the number of black cards is three times that of white cards. A box is chosen at random, and then 5 cards are drawn from that box at random one by one with replacement. Given that 1 black card and 4 white cards are drawn, find the probability that they are drawn from box A.
The answer is 27/28 but i have no idea about the steps