Question about the classroom scene movie "21" ...?!


Question: Prof. Rosa asked Ben to pick one of three doors. Two were losers and one was a winning door. Ben's decision was door 1 and it was random - based on the fact he had a 33.3% chance of choosing the winning door. Prof. Rosa eliminated door 3 saying it was one of the losing doors. He asked Ben if he wanted to choose a different door. Ben said yes because the probability was now higher. This confused me. Now he has a 50% chance of choosing the correct door but he still doesn't know which door is the winning door. Why was changing doors the right decision?


Answers: Prof. Rosa asked Ben to pick one of three doors. Two were losers and one was a winning door. Ben's decision was door 1 and it was random - based on the fact he had a 33.3% chance of choosing the winning door. Prof. Rosa eliminated door 3 saying it was one of the losing doors. He asked Ben if he wanted to choose a different door. Ben said yes because the probability was now higher. This confused me. Now he has a 50% chance of choosing the correct door but he still doesn't know which door is the winning door. Why was changing doors the right decision?

This is known as the Monty Hall problem after the host of "Let's Make a Deal". You see a discussion here: http://en.wikipedia.org/wiki/Monty_hall_...

Its because the door that was eliminated transfers its 33.3 percent over to the other door.



The answer content post by the user, if contains the copyright content please contact us, we will immediately remove it.
Copyright © 2007 enter-qa.com -   Contact us

Entertainment Categories