The contents of three urns are as follows: Urn 1-7 white, 3 black balls.Urn 2 - 4 white, 6 black balls Urn 3 - 2 white and 8 black balls.One of these urns is chosen at random with probabilities 0.20, 0.60 and 0.20 respectively. From the chosen urn two balls are drawn at random without replacement. If both these balls are white, what is the probability that these came from urn 3 ?

Explanation

`E_{1}`= selecting Urn I


` E_{2}`= selecting Urn II


`E_{3}`= selecting Urn III


A= two balls drawn are white.



`therefore P(E_{1})=frac{20}{100} `


`P(E_{2})=frac{60}{100} `


`P(E_{3})=frac{20}{100}`


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