A bag contains 2 white marbles and 7 purple marbles. Two marbles are drawn at random. One marble is drawn and not replaced. Then a second marble is drawn.

a. What is the probability of selecting a purple marble and then a white marble?

b. What is the probability of selecting two white marbles?

c. Is there a greater chance of selecting two white marbles in a row or two purple marbles in a row? Show your work..

3 answers

a. The probability of selecting a purple marble on the first draw is 7/9. Then, there will be only 1 white marble left out of 8 marbles total, so the probability of selecting a white marble on the second draw is 1/8. Therefore, the probability of selecting a purple marble and then a white marble is (7/9) * (1/8) = 7/72.

b. The probability of selecting a white marble on the first draw is 2/9. If a white marble is not replaced, then there will be 1 white marble left out of 8 marbles total, so the probability of selecting a white marble on the second draw is 1/8. Therefore, the probability of selecting two white marbles is (2/9) * (1/8) = 1/36.

c. To calculate the probability of selecting two purple marbles in a row, we need to multiply the probability of selecting a purple marble on the first draw (7/9) by the probability of selecting another purple marble on the second draw, given that a purple marble was already selected and not replaced. Since there are now 6 purple marbles and 8 marbles total left, the probability of selecting a purple marble on the second draw is 6/8. Therefore, the probability of selecting two purple marbles in a row is (7/9) * (6/8) = 7/12.

Comparing this to the probability of selecting two white marbles, we see that 1/36 is less than 7/12, so there is a greater chance of selecting two purple marbles in a row than two white marbles in a row.
could you explain with numbers and make it fast and easy?
Sure, here are the probabilities of each event:

a. Probability of selecting a purple marble and then a white marble:
(7/9) * (1/8) = 7/72

b. Probability of selecting two white marbles:
(2/9) * (1/8) = 1/36

c. Probability of selecting two purple marbles in a row:
(7/9) * (6/8) = 7/12

Therefore, there is a greater chance of selecting two purple marbles in a row than two white marbles in a row.