Thread: Some puzzles View Single Post
2005-10-23, 04:51   #9
Ken_g6

Jan 2005
Caught in a sieve

5×79 Posts

Quote:
 Originally Posted by fetofs Sorry? I can't get this number. I got 213 and my teacher keeps saying that the answer is 214!!! Can you list all the "jumped" numbers?
Jumped numbers:
13
31
103
113
123
130
131
132
133
134
135
136
137
138
139
143
153
163
173
183
193
213

Did you mean appeared together contiguously? Then I get 214. It can't be 213 because that's 213!

P.S. This came from your teacher?

Quote:
 Didn't experts said that not switching is best? If so, not switching is ]n-1/n . That way, we can conclude that the chance is lower . Maybe if the host opens m...
I assume the guest knows that there is one car, and n-1 goats, and that the car is the only goal. Then the guest effectively selects one door he won't open. If the car is behind that door, he loses, but if it's not, eventually he will find it. So his chance of winning is (n-1)/n. I think the not switching thing is for cases where there is more than one car-type goal.

Last fiddled with by Ken_g6 on 2005-10-23 at 04:53