Colored Cards

[mmiguel]

A bag contains three cards, one blue on both sides, one green on both sides, and one with one blue side and one with one green side. You pull one card from the bag and place it on the table. The side showing is blue. What is the probability that the side not showing is also blue?

[phil1882]

we know it can't be the dual green card.

so it can either be blue,blue or blue,green.

i would tend to say 50/50.

[mmiguel]

we know it can't be the dual green card.

so it can either be blue,blue or blue,green.

i would tend to say 50/50.

your sample space isn't quite complete

[vistaptb]

2/3. The side you looked at can either be side 1 of the blue/blue card, side 2 of the blue/blue card, or side 1 of the blue/green card, so 2 out of 3 times the other side will also be blue.