Question

Suppose that:

Urn U1 contains 3 blue balls and six red balls, and

Urn U2 contains 5 blue ball and 4 red balls

Suppose we draw one ball at random from each urn. If the two balls drawn have different colors, what is the probability that the blue ball came from urn U1?

Answer 1

SOLUTION-

URN 1 CONTAINS 3 BLUE BALLS AND 6 RED BALLS

URN 2 CONTAINS 5 BLUE BALLS AND 4 RED BALLS

ONE BALL IS DRAWN AT RANDOM FROM EACH URN.

NOW, SINCE BOTH THE BALLS ARE OF DIFFERENT COLOURS, IF BLUE BALL IS DRAWN FROM URN 1 THEN A RED BALL MUST BE DRAWN FROM URN 2

SO WE APPLY BAYES THEOREM, AND HENCE,

P( BLUE BALL COMES FROM URN 1) =

=

=

=

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