This is a famous paradox probability riddle which has caused a great deal of argument and disbelief from many who cannot accept the correct answer.
Four balls are placed in a bowl. One is Green, one is Black and the other two are Yellow. The bowl is shaken and someone draws two balls from the bowl. He looks at the two balls and announces that atleast one of them is Yellow. What are the chanches that the other ball he has drawn out is also Yellow?
Choices.
A) 1/4 B) 1/5 C) 1/6 D) 1/7 E) 1/8
B   1/5   There are six possible pairings of the two balls withdrawn,   Yellow+Yellow   Yellow+Green   Green+Yellow   Yellow+Black   Black+Yellow   Green+Black.   We know the Green + Black combination has not been drawn.   This leaves five possible combinations remaining. Therefore the chances tbowl the Yellow + Yellow pairing has been drawn are 1 in 5.   Many people cannot accept tbowl the solution is not 1 in 3, and of course it would be, if the balls had been drawn out separately and the color of the first ball announced as Yellow before the second had been drawn out. However, as both balls had been drawn together, and then the color of one of the balls announced, then the above solution, 1 in 5, must be the correct one.
<result>B</result>
This is a famous paradox probability riddle which has caused a great deal of argument and disbelief from many who cannot accept the correct answer.
Four balls are placed in a bowl. One is Green, one is Black and the other two are Yellow. The bowl is shaken and someone draws two balls from the bowl. He looks at the two balls and announces that atleast one of them is Yellow. What are the chanches that the other ball he has drawn out is also Yellow?