A box contains 2 brown cards, 3 black cards, 4 blue cards, and 1 white card. What is the probability of randomly choosing a black card AND THEN a blue card if no cards are replaced?

Answer 1

There are a total of 10 cards.

Then the probability of getting a black card is 3/10.

The probability that choosing a second card is blue given that the first card is black is 4/9.

(The reason for this is when your first pick is a black card out of 10, you are then choosing only 9 cards for the second pick if no cards are replaced.)

Therefore, the probability of randomly choosing a black card AND THEN a blue card if no cards are replaced is (3/10)(4/9) = 2/15