VeritasPrepKarishma wrote:
KK23 wrote:
If two balls are randomly selected from a green urn containing 5 black and 5 white balls and placed into a yellow urn initially containing 5 black and 3 white balls. What is the probability that the yellow urn will contain an equal number of black and white balls after the change?
A.2/9
B.4/9
C.5/9
D.1/3
E.1/9
Can someone please answer this question.....
To have equal number of black and white balls, the yellow urn must have 5 black and 5 white balls. So the balls we select out of the green urn must be both white.
Probability (first ball is white) = 5/10
Probability(second ball is white) = 4/9
Probability (both balls are white) = (5/10)*(4/9) = 2/9
The other way around, total possibilities would be 10C2 = 45 and the selection that 2 white balls are selected out of 5 white balls would be 5C2 = 10.
So probability = 10/45 = 2/9
Please let me know if this approach is correct