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

Home > Logic
Got a Minute? (Posted on 2003-09-10) Difficulty: 3 of 5
You have an infinite amount of timers, each is an hour long (they do not have dials on telling you how long they've been going - they just beep when the time is up). You can set it to double speed at any time, but you cannot set it back to normal speed (eg if you set it to double speed at the start it will last 30 minutes.

Using each timer only once, is it possible to time exactly 25 minutes?

If it is, what is the smallest number of timers you need to do this, and the quickest time you can acheive it?

No Solution Yet Submitted by Lewis    
Rating: 3.6000 (15 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts re: thoughts | Comment 4 of 35 |
(In reply to thoughts by Charlie)

Interesting. I don't have a lot of time to look at this now either, but I expect you are correct that no finite number of clocks will work. But he did say we have a infinite number to work with.

(I can see the whole "Marbles Bonanza" thread starting up again....)

So I expect the answer he has in mind is that you can do it if you use an infinite number of timers.

The interesting part is going to be "what is the quickest time" ie, what is the actual method used.
  Posted by Brian Wainscott on 2003-09-10 12:10:26

Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (5)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information