Brain teaser thread

[Javelin]

0 ft is correct. And yes, it is some fancy trig function(I can't remember which one). Your turn.

 

[zippy]

ut, pythagorean theorem would work if the rope hung perfectly straight from the tops of both poles to the lowest point. Unfortunately, this is not rope that was doused with water then had LN poured on it to solidify it. heheh

 

[thEnEuRoMancER]

There are 13 stones in a jar. 12 stones have exactly the same weight (mass), one stone's weight differs - but we don't know whether it is heavier or lighter than the others.

We've also got a simple scale - two plates, connected with a rod that is pivoted in the middle. This scale only enables us to determine whether objects on one plate are heavier/lighter than the object on the other plate.

The task is to find the stone with deviating weight with only three measurements using this scale.

 

[Fearlss1]

Ok no one will get this one..
First man invented it..
second man bought it and never used it
third man used it and didnt know it was is it

Was is this item hint every 5 guesses..

 

[mHubs]

coffin?

 

[prodigy]

Fearlss1, casket?

 

[geno]

Neuromancer, put 6 stones on each plate. If they eaven out, then the leftover stone is the heaviest. If one is lower than the other, then there must be a combination of stones that'll tell you which is the heaviest within 2 measurements...I'll be figuring that one out

 

[zippy]

thEnEuRoMancER, take the damn rocks in your hands and figure it out down the to last three (for the sake of argument, I'll assume they aren't all the same...) then stick 2 on the scale, if they are the same- then you know it's the third. If they are different, take the...oh say heavier (doesn't matter really) rock and put on the third rock- if this one is heavier then you know that the rock that was taken off and the new rock are the same weight and it's the puny rock.

Heh, a real scientist looks for the easiest way to do something...especially if provided with solid givens.

 

[thEnEuRoMancER]

Hehe, you guys will have to sleep this one over

 

[Javelin]

So 13 balls... split them up into groups of 4,4,5.

Weight 4 vs 4. If they balance then we know that the odd ball is one of the 5.

We weight 3 of the 5 against 3 of the previously weighed ones which we know are normal.

If they balance, weight 1 of the 2 remaining from the group of 5 against a normal... if it balances then the last ball is odd... if it doesnt then it is odd.

If 3 doesn't balance(say heavier)... then weight any 2 of the 3 against each other. If they balance, the 3rd is odd, if they don't the heavier one is odd.

If the first weighting didn't balance(say left was heavier), 1 of the left 4 could be heavy or 1 of the right 4 could be light.

So we have H1, H2, H3, H4(possible heavy ones) and L1, L2, L3, L4(possible light ones)

Weight H1, H2, L1 vs, H3, L2, and a normal(N)

If left side is heavy then either one of H1, H2 is heavy or L2 is light. Weight H1 vs. H2 to find heavy one, if they balance then L2 is light.

If right side heavy then H3 is heavy or L1 is light. Weight H3 against normal to check which one is odd.

If H1,H2,L1 vs. H3,L2,N balances then either H4 is heavy or one of L3 or L4 is light. Simply weigh L3 vs L4 to see if they balance. If they do H4 is heavy if not the light one is odd.

Very tough question.

 

[thEnEuRoMancER]

I'm impressed, your turn!

 

[Javelin]

ok, here's one, but i have to so i won't be here to confirm the answer.

There is a cube which is made up of 1000 mini-cubes(10x10x10). If the outerlayer of mini-cubes were to fall off, how many mini-cubes would be left in the remaining large cube?

 

[thEnEuRoMancER]

8 x 8 x 8 = 512

 

[thEnEuRoMancER]

There are two separate rooms in a building, and there is no way to see from one room into another. You're standing in the room with three simple ON/OFF switches. One of these three switches turns on the lightbulb in the other room. Two other switches are connected to nothing.

Your task is to determine which switch controls the lightbulb. You are allowed to go and check the room with the lightbulb ONCE. You can use the switches as you will.

There are no screwdrivers, electrical plans, hidden cameras and such.

 

[Fearlss1]

damn prodigy69
sorry i am at work and got tied up but yes you are correct..

 

[vi edit]

With one chance to look, I know that I could narrow down the decision to either a 100% or a 50% chance of choosing the right switch.

Simply flip on two of the switches, go look. If the light ain't on, then it's the third one. If the light is on, you have a 50% of choosing the right one.

hmmmmmmm.....

can anybody else help me out

 

[prodigy]

You can't see from one room into the other, but can you see lets say, the light shining on the wall, or a shadow?

 

[thEnEuRoMancER]

After you go look, there won't be any additional information about the state of the lightbulb...

Edit: there is no way to see whether the light is on or off from the first room

 

[prodigy]

Are you alone?

 

[zippy]

Why not just take the face-plate off and see which switch is connected?

Jesus people...EASY answers! Good, hard answers are for idiots. You like that cliche? haha

 

[thEnEuRoMancER]

Yes, you're alone and no, you cannot actually check the cables.

 

[Jumby]

Woo Woo Woo
Flip Switch "A" ON.....Wait a few minutes.........
Flip Switch "A" OFF and Flip Switch "B" ON.
RUN TO the other ROOM IMMEDIATELY!!!!!!

The LIGHT that is ON is for Switch B
The LIGHT that is OFF and WARM is Switch A
And the LIGHT that is OFF and COLD is Switch C

Now back to sleep...................

 

[vi edit]

Jumby...what if they were flourecent?

 

[zbalat]

Which of the following numbers does not belong and why:

1 3 7 11 14 17

 

[thEnEuRoMancER]

Correct, Jumby! Your turn.

A search for "fluorescent lightbulb" yields 1540 hits on google.
A search for "fluorescent light" yields 249000 hits on google.

That's too few hits to reasonably doubt this lightbulb wasn't ordinary but fluorescent from the given description