Tricky Puzzles

Marinus · Post by **Marinus** » Sat Aug 09, 2008 7:39 pm

Ok you both have to share the gold star.

Muzo's explanation is more compact and Lukas's one more complete.

(again too easy isn't it?

)

BTW I didn't give a rule that the X player should begin, I even didn't know there is such rule. I think when two players play this game 10 times, the one time the X starts and the other time the O. When they have to switch each game it should be pretty confusing.

Muzozavr · Post by **Muzozavr** » Sat Aug 09, 2008 9:09 pm

Sorry for the mistake, I checked and indeed there are no rules about starting with X. It simply was a misconception that I was taught. I'd switch every game.

However, the probability that the first player will draw an X is close to 100%. Interesting, huh?
I will think of a puzzle later.

Muzozavr · Post by **Muzozavr** » Sat Aug 09, 2008 9:23 pm

OK, I have it.

If you go first in Tic-Tac-Toe, what move(s) will leave your opponent only ONE safe move?

mqdar · Post by **mqdar** » Sun Aug 10, 2008 12:15 am

Muzo, if you start, then the best option is the go for the middle square. Then, let's say your opponent takes the top-right square. You can then take the top-middle square (one square above the middle square). That leaves your opponent with only one safe move, the blue circle.

- X O
- X -
- O -

Muzozavr · Post by **Muzozavr** » Sun Aug 10, 2008 6:32 am

No, I mean your very FIRST move.
If you do the right thing, you can leave only one safe move for your opponent on the first turn -- out of 8 possiblities! In any other case, you eventually win by creating a double threat.

(And even after that safe move, you STILL can make a trap, but there is no guaranteed win)

mqdar · Post by **mqdar** » Sun Aug 10, 2008 6:42 am

Ok.

It's either of the four corners then? The only safe move your opponent can make is to take the middle square.

peegman · Post by **peegman** » Sun Aug 10, 2008 6:50 am

Can you define safe please?

Muzozavr · Post by **Muzozavr** » Sun Aug 10, 2008 6:53 am

mqdar:
Correct!

peegman:
"Safe" as in "not giving a sure win to your opponent"

mqdar · Post by **mqdar** » Sun Aug 10, 2008 6:53 am

peegman wrote:Can you define safe please?

My idea of safe:
Being safe is being in a comfortable position, where there aren't any present threats in the moment and near future.

ben-09 · Post by **ben-09** » Sun Aug 10, 2008 6:55 am

I've got a puzzle!

A man walks into a bar.

next morning he is found lying on the ground with concussion.

how did this happen

Muzozavr · Post by **Muzozavr** » Sun Aug 10, 2008 6:58 am

1) You're out of turn.
2) This is not a puzzle, but rather a Yes/No question riddle, and is therefore in the wrong topic.
3) This doesn't seem like a good Yes/No question -- there're too many possibilities to account fore.

ben-09 · Post by **ben-09** » Sun Aug 10, 2008 7:01 am

1) huh?

2)ok,sorry

3)ok,sorry

mqdar · Post by **mqdar** » Sun Aug 10, 2008 7:04 am

Did he drink so much that he turned into a hot air balloon and floated up and hit his head on the roof?

Or... maybe he just drank too much?

Muzo, um, I don't have a puzzle, but I'll try to think of one...
Trying again...
Nope.

Marinus · Post by **Marinus** » Sun Aug 10, 2008 8:19 am

Muzozavr wrote:If you do the right thing, you can leave only one safe move for your opponent on the first turn -- out of 8 possiblities!

There are never 8 possibillities. Also if you start in the middle your opponent has only one safe choice; in the corner! There is no difference between which corner then, for the board can be turned 90, 180 or 270 degrees. So if you start in the middle there are only two choice for your opponent: In the corner or in the middle of a side. If he chooses the middle of a side, then the first one has won.

I only know easy ridlles now

Muzozavr · Post by **Muzozavr** » Sun Aug 10, 2008 9:02 am

You're right, Marinus, but not if you play against an average player -- for him there will be 8 APPARENT choices.

Muzozavr · Post by **Muzozavr** » Tue Aug 12, 2008 7:33 pm

Bumping this up with a typical simple-but-hard question:

You have four switches on floor 2, and three of them do nothing. One of them turns on the lamp at floor 1. The lamp is off right now.
You begin at floor 2 and you need to find out which switch controls the lamp. One problem... you're only allowed ONE trip to floor 1.
So, how do you do it? Flipping all switches won't count.

EDIT: Fixed an incredibly stupid typo. ("question" instead of "switches"?! What was I thinking?)

Marinus · Post by **Marinus** » Tue Aug 12, 2008 7:40 pm

What a coincidence!!!

I was almost about posting the same riddle but with 3 switches. I'll PM you about it

Dizzy1 · Post by **Dizzy1** » Wed Aug 13, 2008 12:30 am

Muzozavr wrote:You have four switches on floor 2, and three of them do nothing. One of them turns on the lamp at floor 1. The lamp is off right now.
You begin at floor 2 and you need to find out which switch controls the lamp. One problem... you're only allowed ONE trip to floor 1.
So, how do you do it? Flipping all switches won't count.

You flip 3 switches and wait until they've had time to become warm; if none of them do, then you will know. Or, if one of them becomes warm, you will know.

Muzozavr · Post by **Muzozavr** » Wed Aug 13, 2008 11:11 am

How do you know WHICH one is warm?
You're close at the "warm" idea though. Just a slightly different method.

Marinus · Post by **Marinus** » Wed Aug 13, 2008 4:40 pm

I still don't have an alternative idea for very warm and a little bit warm, now there are 4 switches instead of 3.

Well, I'm an electrician, so I should use a test-meter to see through which switch flows a current, then I don't need to go downstairs at all

Instead of that I could open the switch, connect the wires to see if there's a sparkle

But that's probably not the intended way.

Dizzy1 · Post by **Dizzy1** » Wed Aug 13, 2008 4:58 pm

Muzozavr wrote:How do you know WHICH one is warm?

The switch plate cover will eventually become warm, unless it's a very low watt bulb.

I'm not sure, but could you put your ear up to the switch and hear something?

Muzozavr · Post by **Muzozavr** » Wed Aug 13, 2008 5:26 pm

The switch plate cover could be warm from either of the three switches. Oh wait, do you mean turning them on one after the other? In this case, it might work... IF the switch board WILL become warm.
There is an alternative way, with the lamp itself. Think about it.

Dizzy1 · Post by **Dizzy1** » Wed Aug 13, 2008 5:46 pm

This would work, but I don't know if it's what you're looking for:

Go downstairs, turn out all the lights in the house, put the lamp as close to the stairway as possible (or use an extension cord), go back upstairs and flip 3 switches, one at a time.

Or...

Get another small appliance that makes a noise when it's turned on, go downstairs, unplug the lamp and replace it with the small appliance. Then you will hear which switch works.

Muzozavr · Post by **Muzozavr** » Wed Aug 13, 2008 6:01 pm

No, sorry. What I meant is that the lamp can also be warm -- now find a way to make it work for 4 switches.

Marinus · Post by **Marinus** » Wed Aug 13, 2008 6:21 pm

Ok let's give it another try

My 3 switches riddle was:
Turn 1 on, wait 5 minutes, then 1 off and 2 on.
Then go check, if the lamp is:
off and warm = 1
on = 2
off and cold = 3

My idea for the 4 switches was:
1 on, wait 5 minutes
2 on and 1 off, wait 5 minutes
3 on and 2 off, then go check, if the lamp is:
off and a little bit warm = 1
off and very warm = 2
on = 3
off and cold = 4

But there was a better solution, so maybe this:
1 and 2 on, wait 5 minutes
1 still on, 2 off and 3 on, then go check very quick
on and very warm even the surrounding things = 1
off and warm = 2
on but surrounding things are still cold = 3
off and cold = 4

If this isn't correct you may tell me.

Muzozavr · Post by **Muzozavr** » Wed Aug 13, 2008 6:24 pm

YES!!!
The last solution is correct.
(As my father said: "and if you bring a thermometer..."

)

Muzozavr · Post by **Muzozavr** » Fri Aug 22, 2008 9:35 pm

Since absolutely no one else decided to continue, I will. This one is an image file.

Dizzy1 · Post by **Dizzy1** » Fri Aug 22, 2008 9:53 pm

Is there a question also?

Marinus · Post by **Marinus** » Fri Aug 22, 2008 9:56 pm

After a while everything, whatever it is, will FADE away

You're right Muzo, but I wonder if you know why.

Lutz · Post by **Lutz** » Fri Aug 22, 2008 10:47 pm

Marinus wrote:After a while everything, whatever it is, will FADE away

And after that it is 57005 ...