Question

Four balls are placed in a bowl. one green, one black and two yellow. the bowl is shaken and someone draws two balls from the bowl. he looks at the balls and announces that at least one of them is yellow. what are the chances that the other drawn ball is yellow?

Answer 1

1/5 chance

Explanation:

well their are 4 balls and 2 chosen

their is 1/2 chance or pulling a yellow

1/4 chance of pulling a black and green

Y1 Y2,Y1 B,Y1 G,Y2 Y1,Y2 B,Y2 G,B Y1,B Y2,B G,G Y1,R Y2,G B

so their is a 1/5 chance of pulling it