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Ratings 3

Death by drawing?
How many?
How many?2

Comments 6

Fork in the road

Another solution: point to one fork and say to one of the twins, "If I asked you if this was the path to the money, would you say yes?" Say it was the right path. If you asked the truth-teller, he of course would say yes. If you asked the liar outright if it was the right path, he would say no. But to answer the given question, he would lie and say yes. The same reasoning applies if it was the wrong path. Both would answer "no."

3 Coins

I think the answer is 75%. It doesn't matter what the odds were to get you to the final flip (this is not like the famous Monty Hall problem that requires you to make a choice at the beginning). We know the coin cannot be the tails coin. If it is the heads coin (odds of which being 50%), then of course the third flip will be heads. If it is the honest coin (also 50%), then 50% of the time it will come up heads, which means a composite probability of 25%. Thus, 3 out of 4 times it should be heads.

The Monty Hall Problem

This problem was in Marilyn vos Savant's PARADE Magazine column about 20 or so years ago. She got dozens of abusive letters from math PhD's and other pointy-headed academia telling her how wrong she was. She published some of them, including their names. Hilarious!

Birthday Problem (Classic)

I saw a fellow telling Johnny Carson about this problem on the Tonight Show many years ago. Carson looked incredulous and then asked the audience, "Does anybody here have a birthday on..." and then said his birthday. When no one answered, he looked at the guy like he was nuts. It may have been that someone did have the same birthday as Carson but didn't speak up. But even if he had, that wasn't what the guest had said. For a 50% likelihood of someone having a GIVEN birthday, you need about 183 people. But for a 50% likelihood of ANY TWO people in a group having the SAME birthday, you need only 23 people.

The Price Is Right

I don't believe this, since taxes would put the price at more than an even dollar figure even if the price was a whole dollar amount. The real reason is that the customer sees a price P as [P], where [x] = maximum integer < = x. So a price of $8.95 or $8.99 is seen as $8.00, even though it is nearly $9.00. Why do you think gasoline is priced to nine-tenths of a cent?

Cooking Time

WRONG! You said, "At this time 8 minutes have passed." No, only seven minutes have passed. It can't be done. Ten Minutes yes, but not 9.


Submitted Puzzles 3

3 8 How many?
As I was going to St. Ives, I met a man with seven wives. Each wife had seven sacks. Each sack has seven cats. Each cat had seven kits. Kits, cats, sacks, and wives, How many were going to St. Ives? ...
1 2 How many?2
How many people contribute to MindCipher?
6 7 Death by drawing?
You are a prisoner in a strange foreign land, and a random drawing will decide your fate. You are given 2 bags, 10 white marbles, and 10 black marbles. You are to place the marbles in the bags in any a ...