Here's a question to ask your Christmas Dinner guests while you wait for the turkey:
I am holding a cup with two dice in it. I can see that at least one of the two dice is showing a two. I ask myself "if at least one die in my cup is showing a two what are the odds that the other die is also showing a two?" I immediately reason that there are only six sides on the other die so the answer must be 1 out of 6. I say to my guests am I correct?
Then one of my guests who is a mathematician immediately announces that the correct answer should be 1/11.
But I say I am looking at the dice in the cup and at least one of the two dice is definitely a two, so the answer is 1/6 for the faces on the other die.
The mathematician says he's not looking at the dice so his answer of 1/11 is correct.
But I say I am looking at the dice and I can see one die plain as day.
Now the question for your guests: which answer fits reality?