Urn A contains 6 red and 4 black balls and urn B contains 4 and 6 black balls. One ball is drawn at random from urn A and B placed in urn B. Then one ball is drawn at random from urn and placed in urn. A If one ball is now drawn at random from urn A, the porbability that it is red.

Answer

B, C

Explanation

Let R be drawing a red ball and B for drawing a black ball, then required probability
`=RRR+RBR+BRR+BBR`
`=((6)/(10)xx(5)/(11)xx(6)/(10))+((6)/(10)xx(6)/(11)xx(5)/(10))+((4)/(10)xx(4)/(11)xx(7)/(10))((4)/(10)xx(7)/(11)xx(6)/(10))`
`=(640)/(1100)=(32)/(55)`