Please solve the question by Bayes theorem?

There are three urns containing black, red and green balls. urn 1 contains 4 black, 5 red and 3 green balls urn 2 contains 7 black, 4 red and 4 green balls urn three contains 6 black, 6 red and 5 green balls. An urn is chosen and ball is picked if the ball picked is green find the probability it has come from urn 3.

1 Answer
Dec 1, 2017

300 / 827

Explanation:

P[ "Urn 3|Green" ] P[ "Green" ] = P[ "Green|Urn 3" ] P[ "Urn 3" ]

=> P[ "Urn 3|Green" ] = (P[ "Green|Urn 3" ] P[ "Urn 3" ]) / (P[ "Green" ])

= ((5/17) (1/3)) / [ ((3/12) + (4/15) + (5/17))/3 ]

= (5/17) / [ 3/12 + 4/15 + 5/17 ]

= 5 / [ 51/12 + 68/15 + 5 ]

= 5 / [ (255 + 272 + 300 ) / 60 ]

= 300 / 827