Question

Consider the following problem: You stop on the street between errands to engage in a shell game with a street vendor. The vendor shows you a two-headed penny under one shell, a two-tailed penny under the second shell and a fair penny (one head and one tail) under the third shell. He shuffles the shells around and then you choose a shell. He shows you that under the shell is a penny with the head side up. He is willing to bet you $5 that it is the two-headed penny. He says it cannot be the two-tailed penny because a head is showing. Therefore, he says there is a 50-50 chance of it being the tw

Answer 1

If you choose the shell with the two-tailed penny, what does the vendor do?

Answer 2

He shuffles the shells around and then you choose a shell.

Answer 3

sorry, He says it cannot be the two-tailed penny because a head is showing. Therefore, he says there is a 50-50 chance of it being the two-headed coin.

Answer 4

google monte hall problem and you will find your solution

Answer 5

thanks satellite73

Answer 6

you will see that it is \(\frac{1}{3}\)
problem was cut off, but you can work by analogy

Answer 7

Well yeah, but if you choose the shell with the two tailed penny what happens? This does look like a version of the three door problem, but I think you might have the description wrong. When I choose a shell, does the vendor reveal the one I chose or one of the others?

Answer 8

i copied and paste what the instructor had

Answer 9

But that's incomplete... if you pick a shell at random, there's a 1/3 chance it'll be the two tailed penny. What does the vendor do in that case?
Anyway I suggest you start here
http://en.wikipedia.org/wiki/Monty_Hall_problem