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An urn contains different colored marbles. The probability of drawing two green marbles from the urn without replacement is 3/20 , and the probability of drawing one green marble is 2/5 .

What is the probability of drawing a second green marble, given that the first marble is green?


3/50

1/2

3/8

1/5

User Montezuma
by
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2 Answers

5 votes

Answer:

3/50

Explanation:

User Nico Burns
by
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5 votes

Answer:

The probability of drawing a second green marble, given that the first marble is green is:


(3)/(8)

Explanation:

Let A denote the event that first marble is green.

B denote the event that the second marble is green.

A∩B denote the event that both the marbles are green.

Let P denote the probability of an event.

We are asked to find:

P(B|A) i.e. probability of drawing a second green marble, given that the first marble is green.

We know that:


P(B|A)=(P(A\bigcap B))/(P(A))

Probability of drawing one green marble is 2/5 i.e.


P(A)=(2)/(5)

The probability of drawing two green marbles from the urn without replacement is 3/20 i.e.


P(A\bigcap B)=(3)/(20)

Hence, we have:


P(B|A)=((3)/(20))/((2)/(5))\\\\\\i.e.\\\\\\P(B|A)=(3* 5)/(20* 2)\\\\\\P(B|A)=(3)/(8)

User Janovak
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