In need of a good riddle...

[blackdogdeek]

Originally posted by: Kelnoen
Rope one: Just fold one piece of rope in half twice, that gives you 1/4 of the rope length, burn it.

Caps: Do they know if other people guess correctly?

oh and btw, Gry (verb) - To rage or roar.

the ropes do NOT burn at constant rates.

 

[letdown427]

Originally posted by: blackdogdeek
the ropes do NOT burn at constant rates.

You are the winnar with your previous post

 

[Billzie7718]

Originally posted by: letdown427

Originally posted by: DaShen
That one is easy. It is just taking the fastest with the slowest walker, and going back and using the fastest with slowest the whole time to limit the lag time going back.

But that gives 19minutes, so apparently not.

EDIT: As Scott said

It can be done in 17 min
10 & 5 = 10 min
5 & 1 = 5 min
2 & 1 = 2 min
Total = 17 min

 

[DaShen]

You are in a musky-empty room with no windows save for the man swinging from a noose in the middle of the room. How did the man kill himself?

A man lives on the 13th floor. Everyday he wakes up, cooks breakfast, kisses his wife, rides down the elevator, and goes to work. One day the elevator stops on the 5th floor and the man relizes his wife just died. What happened?

Why are sewer grates round? Explain.

There is an island in the middle of a lake or moat. The island is perfectly square the moat is perfectly square and has a distance between the ouside and island of 10 yards.
I am given 2 planks that are 9 yards (FIXED) long. How do I get across?

Somewhere in a very distant place, there is a very special village. And what's so special? Well, in this village there is a barber. And a very special barber. The barber cuts the hair of EVERYBODY in the village that doesn't cut his own hair.
But who cuts the barber's hair? **Taken from a website, but any programmer should understand this one**

Given that
* a mother is 21 years older than her child, and
* in 6 years the child will be 5 times younger than the mother,
I ask you: where is the father? (This one is just funny)

Enjoy!!

 

[DaShen]

Originally posted by: blackdogdeek

Originally posted by: DaShen
2 ropes (each of varying lengths)

Both ropes when lit on one end burn for an hour. Both rope at different points burn at variable rates.

You are given a box of matches and told to measure 15 minutes.

How do you measure it?

here is a guess.

on one rope, light both ends at the same time and simultaneously light only one end of the other rope. presumably, when the dual-lit rope finishes burning, 1/2 hour will have transpired. when that happens light the other end of the other rope and the time it takes for the remainder of that rope to burn should be 1/4 hour.

if you want to be able to record 15 minutes at any time then when the first rope finishes burning just put out the fire on the second rope. whenever you want to record your 15 minutes, light both ends simultaneously.

:thumbsup:

 

[DaShen]

Originally posted by: ScottSwingleComputers

Originally posted by: DaShen
This one is from an old thread.

I have 100 captives.

I tell them that tomorrow I will line them up in single file and place a black or white cap on top of each persons head. Every person can see
If you guess the color of the hat on your head, I will set you free, otherwise I will kill you.

There is a plan to get 99% guaranteed free.

Ask your neighbor?

The only thing you can say is your hat color.

 

[letdown427]

Caps:

First guy says the colour of the cap in front of him (or behind, gues sit depends where DaShen starts killing)

He may die, he may not. Next guy now knows the colour of his hat. He can say that colour, and if it's different to the enxt one in the line, cough/do some other signal and so it continues. Then there's the spiteful guy that wants to see the next guy dead... but yeh, that would work.

 

[Kelnoen]

Originally posted by: blackdogdeek

Originally posted by: Kelnoen
Rope one: Just fold one piece of rope in half twice, that gives you 1/4 of the rope length, burn it.

Caps: Do they know if other people guess correctly?

oh and btw, Gry (verb) - To rage or roar.

the ropes do NOT burn at constant rates.

whoops lol

 

[DaShen]

Originally posted by: Kelnoen
Rope one: Just fold one piece of rope in half twice, that gives you 1/4 of the rope length, burn it.

Caps: Do they know if other people guess correctly?

oh and btw, Gry (verb) - To rage or roar.

Variable lengths, and variable burn rates, you cannot do this.

 

[DaShen]

Originally posted by: letdown427
Caps:

First guy says the colour of the cap in front of him (or behind, gues sit depends where DaShen starts killing)

He may die, he may not. Next guy now knows the colour of his hat. He can say that colour, and if it's different to the enxt one in the line, cough/do some other signal and so it continues. Then there's the spiteful guy that wants to see the next guy dead... but yeh, that would work.

No sound except for your hat color. Sorry.

I had one similar to your that dealt with variable lag times to say you hat color. It was accurate, but once timing was taken out of the equation, I had to rethink the problem

 

[letdown427]

Originally posted by: DaShen
You are in a musky-empty room with no windows save for the man swinging from a noose in the middle of the room. How did the man kill himself?

With the light bulb cable?

A man lives on the 13th floor. Everyday he wakes up, cooks breakfast, kisses his wife, rides down the elevator, and goes to work. One day the elevator stops on the 5th floor and the man relizes his wife just died. What happened?

His wife rides the elevator with him, and died. His wife works the elevator. His wife lives on the 5th Floor and is laying dead by the elevator.

Why are sewer grates round? Explain.

Meh

There is an island in the middle of a lake or moat. The island is perfectly square the moat is perfectly square and has a distance between the ouside and island of 10 yards.
I am given 2 planks that are 9 feet long. How do I get across?

One plank across a corner, the other from the middle of that to the island. Makes a kinda T shape.

Somewhere in a very distant place, there is a very special village. And what's so special? Well, in this village there is a barber. And a very special barber. The barber cuts the hair of EVERYBODY in the village that doesn't cut his own hair.
But who cuts the barber's hair? **Taken from a website, but any programmer should understand this one**

The very special barber does

Given that
* a mother is 21 years older than her child, and
* in 6 years the child will be 5 times younger than the mother,
I ask you: where is the father? (This one is just funny)

In a slum, struggling to pay child support

Enjoy!!

Caps:

They shout the hat colour if it's different, and just say it if it's the same. Or say it slowly/fast.

 

[juills]

Given that
* a mother is 21 years older than her child, and
* in 6 years the child will be 5 times younger than the mother,
I ask you: where is the father? (This one is just funny)

Enjoy!![/quote]

At the local pub...

 

[Vegitto]

Originally posted by: DaShen
I am sitting in the middle of a lake on a boat that floats. I have a rock in the boat. I throw it overboard and the rock sinks to the bottom of the lake. The the lake sea level rise or lower or stay the same.

*HINT* "Eureka"

A lake doesn't have a sea level?

 

[DaShen]

the first one, the guy used a block of ice and hung himself from the a noose. as soon as he was up on the noose he kicked the block of ice away. The ice melted making the room musky.

The wife was on a respirator and the power went out.

Sewer grates are round so as to not allow the grates to fall through.

Correct

Place does not exist (dne) since it is a paradox

(x+21)+6 = (x+6) * 5
Solve for x (there are 12 months in a year ) :laugh:
Where is the father?

 

[blackdogdeek]

Originally posted by: DaShen

Originally posted by: letdown427
Caps:

First guy says the colour of the cap in front of him (or behind, gues sit depends where DaShen starts killing)

He may die, he may not. Next guy now knows the colour of his hat. He can say that colour, and if it's different to the enxt one in the line, cough/do some other signal and so it continues. Then there's the spiteful guy that wants to see the next guy dead... but yeh, that would work.

No sound except for your hat color. Sorry.

I had one similar to your that dealt with variable lag times to say you hat color. It was accurate, but once timing was taken out of the equation, I had to rethink the problem

could the signal be: if i see a similar colored hat on the next person's head i keep my eyes open when i say my color, otherwise, i close my eyes when i say my color.

or does the solution not require a signal?

 

[DaShen]

Originally posted by: blackdogdeek

Originally posted by: DaShen

Originally posted by: letdown427
Caps:

First guy says the colour of the cap in front of him (or behind, gues sit depends where DaShen starts killing)

He may die, he may not. Next guy now knows the colour of his hat. He can say that colour, and if it's different to the enxt one in the line, cough/do some other signal and so it continues. Then there's the spiteful guy that wants to see the next guy dead... but yeh, that would work.

No sound except for your hat color. Sorry.

I had one similar to your that dealt with variable lag times to say you hat color. It was accurate, but once timing was taken out of the equation, I had to rethink the problem

could the signal be: if i see a similar colored hat on the next person's head i keep my eyes open when i say my color, otherwise, i close my eyes when i say my color.

or does the solution not require a signal?

Remember that the person in the back knows all the colors of all the people in front of him. What is the quickest way to dispense the most information about hat colors to the others by just saying one of the colors?

 

[DaShen]

Originally posted by: Vegitto

Originally posted by: DaShen
I am sitting in the middle of a lake on a boat that floats. I have a rock in the boat. I throw it overboard and the rock sinks to the bottom of the lake. The the lake sea level rise or lower or stay the same.

*HINT* "Eureka"

A lake doesn't have a sea level?

lake level then :roll:

Come on, volume displacement and density.
ever put a tube into a pool and sat on it? what does it do?
how about when the tube is not filled with air? What then?

 

[drinkmorejava]

If you must:
http://presents.elliian.com/riddle/

 

[Billzie7718]

You are at a well. You have an empty jug that can hold eight quarts of water. You also have two empty jars, one holding five quarts, the other holding three quarts.

You need to measure out exactly four quarts. How you do dat?

 

[Billzie7718]

Originally posted by: DaShen

Originally posted by: Vegitto

Originally posted by: DaShen
I am sitting in the middle of a lake on a boat that floats. I have a rock in the boat. I throw it overboard and the rock sinks to the bottom of the lake. The the lake sea level rise or lower or stay the same.

*HINT* "Eureka"

A lake doesn't have a sea level?

lake level then :roll:

Come on, volume displacement and density.
ever put a tube into a pool and sat on it? what does it do?
how about when the tube is not filled with air? What then?

The water level will stay the same because it was already displaced when the rock was place in the boat.

 

[letdown427]

Originally posted by: Billzie7718
You are at a well. You have an empty jug that can hold eight quarts of water. You also have two empty jars, one holding five quarts, the other holding three quarts.

You need to measure out exactly four quarts. How you do dat?

1. Empty the 3 quarts into well for all I care.

2. Fill 3 jug from 5 jug to get 2 left in 5 jug. Put that 2 into the 8 jug.

3. Fill 5 from well.

4. Empty the 3 jug again...

5. etc.

6. ...

7. Profit ?

 

[brikis98]

2 ropes (each of varying lengths)

Both ropes when lit on one end burn for an hour. Both rope at different points burn at variable rates.

You are given a box of matches and told to measure 15 minutes.

How do you measure it?

some1 got this right already: at the same time, light both ends of one rope and one end of the 2nd rope... when the two ends of the first rope touch, exactly 30 minutes has passed. at that moment, light the other end of the second rope. when the two ends of that rope have touched, exactly 15 more minutes will have passed.

You have 2 coins with a total value of 15 cents, and one of them is not a dime. What coins are they?

If you say it fast enough people really seem to stumble.

... well, the one coin that isn't a dime is a nickel and the other coin IS a dime.

it is raining outside and 4 people in a car need to get to the front door of the building but there is only 1 umbrella. one person must bring the umbrella back to get another person after each trip from the car to the door. the pair walking from the car to the door can only walk as fast as the slower person can walk. one person takes 10 minutes to make the trip, one person takes 5 minutes to make the trip, one person takes 2 minutes to make the trip and the last person takes 1 minute to make the trip.

what is the least amount of time it will take to get everyone from the car to the building?

1 + 2 go together, 1 goes back
5 + 10 go together, 2 goes back
1 + 2 go together
total = 17 minutes

I am sitting in the middle of a lake on a boat that floats. I have a rock in the boat. I throw it overboard and the rock sinks to the bottom of the lake. The the lake sea level rise or lower or stay the same.

*HINT* "Eureka"

i believe the water level will actually rise... the boat has much more surface area/volume, so with the added mass of a rock in it, it displaces more water than the rock alone would.

have 100 captives.

I tell them that tomorrow I will line them up in single file and place a black or white cap on top of each persons head. Every person can see
If you guess the color of the hat on your head, I will set you free, otherwise I will kill you.

There is a plan to get 99% guaranteed free.

the very first guy to answer looks ahead of him and counts the number of, say, black hats. if that number is odd, he says "black". if that number is even, he says "white". he has a 50/50 chance of being right. however, everyone in front of him, if they aren't idiots, now has a 100% chance of being right.

when it's the next guy's turn to answer, he counts the number of black hats in front of him. if the first guy said black (=odd) and there are still an odd number of black hats in front of him... then his hat must be white... if there are an even number of black hats in front of him... then his hat must be black... similarly, if the first guy said white (=even), and the # of black hats is still even, then his hat is white, otherwise it's black.

you repeat the same process down the line, just seeing if the oddness/evenness of the # of black hats in front of you stays the same as what the guy before you said.

Why are sewer grates round? Explain

the expected answer is so that they can't fall in... but there are many other good ones: so that you can roll them (they are heavy!), drills are round, pipes are round, etc...

You are at a well. You have an empty jug that can hold eight quarts of water. You also have two empty jars, one holding five quarts, the other holding three quarts.

You need to measure out exactly four quarts. How you do dat?

fill the three quart jug. pour all 3 quarts into the five quart jug. fill the three quart jug again. pour everything that will fit into the five quart jug. this will leave 1 quart in the 3 quart jug and 5 quarts in the 5 quart jug. empty the 5 quart jug. pour the 1 quart from the 3 quart jug into the 5 quart jug. fill the 3 quart jug again. pour those 3 quarts into the 5 quart jug. you now have 4 quarts.



EDIT: forgot to mention. i've had MANY of these as interview questions (for software jobs).

 

[Kelnoen]

Originally posted by: letdown427

Originally posted by: blackdogdeek
the ropes do NOT burn at constant rates.

You are the winnar with your previous post

I presumed you had to time 15 minutes from when you were given the matches :S

 

[sswingle]

Originally posted by: Billzie7718
You are at a well. You have an empty jug that can hold eight quarts of water. You also have two empty jars, one holding five quarts, the other holding three quarts.

You need to measure out exactly four quarts. How you do dat?

Wasnt this in a movie? Die Hard 3 maybe?

 

[blackdogdeek]

here is a question i was asked on a telephone interview so i couldn't use any scrap paper.

you have a list of the numbers from 1 to N placed in a random order. one of the numbers is missing.

how can you determine the number in linear time?