one card is white on both sides;
one card is white on one side, black on the others,

I randomly blindly pick one, and see a white side, what's the chance that the other side is also white?

Question

one card is white on both sides;
one card is white on one side, black on the others,

I randomly blindly pick one, and see a white side, what's the chance that the other side is also white?

blacksteel · Answer

2/3, I believe.

There are 3 white faces, and two of them have a white face on the other side.

kinggeorge · Answer

It should have been $2/3$.

What he ^^ said.

aravindg · Answer

2/3

anonymous · Answer

but i mean, i have equal chance of picking either one of the 2 cards, so why it's not 1/2 ?

kinggeorge · Answer

|dw:1334638936333:dw|There are three white sides to see. Of those 3, for two of them you will see that the other side is also white.