# Thread: probability - coin flip with

1. ## probability - coin flip with

Hi all.

I have a question. Let's say I have two coins, one that's "honest" with heads on one side and tail on the other, and one "dishonest" with heads on both sides. If I then put my hand in my pocket and pick one up without looking at it, flip it, and get heads, then what is the probability I have the "honest" coin?

My initial thought is that the probability is 50%, as I pulled it out of my pocket without looking, but I have a feeling I am wrong. How do I calculate this?
Help would be much appreshiated!

2. Actually, I changed my mind, I think the probability is 1/3. If I flip both the coins I will get 3 heads and one tail. One of these heads will be on the "honest" coin, therefore 1/3. Does this seem right?

3. yes - 1/3 is correct.

4. great, thanks!