Math Is Fun Forum

Old thread,  much older question. It's not solvable unless you know if Monty will always show you a goat, or will show you a goat only if you originally chose the car; also does he know where the car is (and if not, what happens if he reveals the car?)
Example: I have a dollar in one fist, choose left or right?  Are the odds 1/2-1/2 if I'm waving one fist at you begging you to pick it? (And are you my to grandchild whom I'm trying to give a dollar, or are you some guy in the bar?)  Are the odds 1/2-1/2 if you've observed in a sufficiently large number of trials that I always put the dollar in my right hand when I play this game? Are the odds 1/2-1/2 if you can see the dollar coming out of my right hand?