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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.


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User Moogs
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2 Answers

4 votes

Answer:

Explanation:

in general, the probability of some event

= number of times that event can happen/total number of possible outcomes

so ...

you have 2 white and 7 purple

prob of purple = 7/9

then

prob of white = 2/8 , there are only 8 left since you drew one already.

prob(purple, then white) = (7/9)(2/4) = 7/36

prob(2 whites) = (2/9)(1/8) = 1/36

prob(2 purples) = 7/9(6/8) = 7/12

and of course 7/12 > 1/36

clearly , since you had more purples than whites, the chances of getting purples would be greater than the chances of getting whites.

User Petr Rastegaev
by
4.0k points
2 votes

Answer:

a: 7/36

b:1/36

c: 7/12 > 1/36

Explanation:

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User ShivRaj
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4.1k points