All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Logic
Guess my Number (Posted on 2004-12-20) Difficulty: 2 of 5
The Mad Hatter poured Alice another cup of tea and set the teapot down.

"May I please have one of those biscuits?" asked Alice rather timedly, rather taken aback by the sight of her present company.

"A biscuit?? Oh, I don't know. Those are the March Hare's special un-birthday biscuits, don't you know. Can she have a biscuit, March ?" asked the Hatter.

"A biscuit?? One of mine? Hurmph. Ok, I'm thinking of an integer from one to three (inclusive). If you get it, you can have a biscuit. If not, I'm afraid you'll just have to leave" said the March Hare, leaning back.

"Oh goodness, I don't know" said Alice worriedly. "Couldn't I just get a hint?"

"Oh, all right..." the March Hare sighed. "You get to ask me one yes-or-no question, that's all"

Alice thought for a moment, then smiled, knowing exactly what to ask.

What question should Alice ask?

See The Solution Submitted by Sam    
Rating: 3.7647 (17 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts re: Independent solution | Comment 12 of 32 |
(In reply to Independent solution by Tristan)

Alice puts her right hand behind her back.  She asks, "Is the number four less than the number of fingers up on my right hand, or is it a two?"  (This question is asked as a yes-or-no question, not a which-is-it question.)

If the number is 3, the March Hare will say, "No."  If the number is a 2, he will say, "Yes."  If it is a 1, he will say "I don't know."

I don't think that he can know the answer to any of them if he doesn't know how many fingers she is holding up. If the number is 2 then it could be yes or no depending on how many fingers she has up. Yes if she's holding up 4. No if it's anything else. If the number is 3 and she is holding up 4 fingers or less then the answer is no. But if she's holding up 5 fingers then it's yes.

  Posted by Danny on 2004-12-21 15:30:09
Please log in:
Remember me:
Sign up! | Forgot password

Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (3)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Copyright © 2002 - 2020 by Animus Pactum Consulting. All rights reserved. Privacy Information