Urn A contains 4 yellow balls and 6 red balls. Urn B contains 10 yellow balls and 5 red balls. Urn C contains 11 yellow balls and 12 red balls. An urn is picked randomly (assume that each urn is equally likely to be chosen), and then a ball is picked from the selected urn. What is the probability that the chosen ball came from urn B, given that it was a yellow ball?

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Answer:

The probability that the chosen ball came from urn B, given that it was a yellow ball is [tex]\frac{230}{533}[/tex].

Step-by-step explanation:

Given information:

Urn A : 4 yellow and 6 red balls

Urn B : 10 yellow and 5 red balls

Urn C : 11 yellow and 12 red balls

Let A,B and C are events that bag A,B and C are selected respectively.

[tex]P(A)=P(B)=P(C)=\frac{1}{3}[/tex]

E be the event that a yellow ball is drawn.

The probability that a yellow ball is drawn from urn A.

[tex]P(\frac{E}{A})=\frac{4}{10}=\frac{2}{5}[/tex]

The probability that a yellow ball is drawn from urn B.

[tex]P(\frac{E}{B})=\frac{10}{15}=\frac{2}{3}[/tex]

The probability that a yellow ball is drawn from urn C.

[tex]P(\frac{E}{C})=\frac{11}{23}[/tex]

We need to find the probability that the chosen ball came from urn B, given that it was a yellow ball.

[tex]P(\frac{B}{E})=\frac{P(B)P(\frac{E}{B})}{P(A)P(\frac{E}{A})+P(B)P(\frac{E}{B})+P(C)P(\frac{E}{C})}[/tex]

[tex]P(\frac{B}{E})=\frac{\frac{1}{3}(\frac{2}{3})}{\frac{1}{3}(\frac{2}{5})+\frac{1}{3}(\frac{2}{3})+\frac{1}{3}(\frac{11}{23})}[/tex]

[tex]P(\frac{B}{E})=\frac{230}{533}[/tex]

[tex]P(\frac{B}{E})\approx 0.43152[/tex]

Therefore the probability that the chosen ball came from urn B, given that it was a yellow ball is [tex]\frac{230}{533}[/tex].

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