Question

How can i find the probabilities in questions like these (there are two different probabilities???)

Question: A bag contains 12 red marbles and 8 white marbles. A marble is selected, KEPT OUT OF THE BAG, and then another marble is selected. What is P(red, then white)? Write the answer as a decimal.

Answer 1

Find the probability of picking a red marble. This would be 12 out of 20. The, take 1 away from the denominator because you already picked a marble. So then find the probability of picking white marble, which is 8 out of 19. The multiply them to get 84 out of 380