Question

There are 6 black balls and 5 red balls in an urn. If 4 balls are drawn without replacement, what is the probability that exactly 2 black balls are drawn? Express your answer as a fraction or a decimal number rounded to four decimal places.

Answer #1

There are a total of 6+5=11 balls in the urn.

Total number of ways of drawing 4 balls without replacement is

Number of ways of getting 2 black balls (and hence 2 red balls) is

the probability that exactly 2 black balls are drawn is

ans: the probability that exactly 2 black balls are drawn is 0.4545 (or 5/11)

There are 9 black balls and 5 red balls in an urn. If 4 balls
are drawn without replacement, what is the probability that at
least 3 black balls are drawn? Express your answer as a fraction or
a decimal number rounded to four decimal places.

There are 5 black balls and 10 red balls in an urn. If 3 balls
are drawn without replacement, what is the probability that no
black balls are drawn? Express your answer as a fraction or a
decimal number rounded to four decimal places.

There are 8 black balls and 7 red balls in an urn. If 4 balls
are drawn without replacement, what is the probability that no more
than 1 black ball is drawn? Express your answer as a fraction or a
decimal number rounded to four decimal places.

Urn 1 contains 4 red balls and 3 black balls. Urn 2 contains 1
red ball and 3 black balls. Urn 3 contains 4 red balls and 2
black balls. If an urn is selected at random and a ball is
drawn, find the probability that it will be red.
Enter your answer as a fraction in simplest form or a decimal
rounded to 3 decimal places.
P(red)=

Urn 1 contains 7 red balls and 3 black balls. Urn 2 contains 4
red balls and 1 black ball. Urn 3 contains 4 red balls and 3 black
balls. If an urn is selected at random and a ball is drawn, find
the probability that it will be red.
enter your answer as a decimal rounded to 3 decimal places

Urn 1 contains 7 red balls and 3 black balls. Urn 2 contains 1
red ball and 3 black balls. Urn 3 contains 3 red balls and 1 black
ball. If an urn is selected at random and a ball is drawn, find the
probability that it will be red.
Enter your answer as a fraction in simplest form or a decimal
rounded to 3 decimal places.

An urn contains 4 red balls and 6 green balls. Three balls are
chosen randomly from the urn, without replacement. (a) What is the
probability that all three balls are red? (Round your answer to
four decimal places.) (b) Suppose that you win $50 for each red
ball drawn and you lose $25 for each green ball drawn. Compute the
expected value of your winnings.

An urn contains 1 white, 2 black, 3 red, and 4 green balls. If 6
balls are selected randomly (without replacement) and X represents
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(calculate this value directly by using the probability mass
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Urn A has 1 red and 2 black balls. Urn B has 2 red and 1 black
ball. It is common knowledge that nature chooses both urns with
equal probability, so P(A)=0.5 and P(B)=0.5. A sequence of six
balls is drawn with replacement from one of the urns. Experimental
subjects do not know which urn the balls are drawn from. Let x
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urn are red? Round your answer to three decimal places.

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