Riddle me this, Batman!

[Thomas Veil]

My daughter was asked this riddle in a class in school. She gets extra credit if she gets it right.

A farmer has to get a fox, a goose, and a bag of corn across a river in a boat which is only large enough for her and one of these three items. She does not want to leave the fox alone with the goose nor the goose alone with the corn. How can she get all these items across the river?

Now: keep in mind that you must think of both sides of the river. The first solution that tends to come to mind is that she takes the goose across first. But if she comes back for either the fox or the corn, she'll have to leave one of those alone with the goose on the other side of the river. And that doesn't work.

The only solution that I can think of -- and it's not a truly satisfying one -- is the one below. I've made it a "spoiler" because I don't want to prejudice your thinking. You may not want to read it until after you've thought it through yourself, because frankly I think I'm going down the wrong road.

(Click-and-drag if you want to view: )

The farmer takes the goose first, leaves it in the middle of the river (it's a goose, remember?), then takes the fox across, then takes the corn across, and then comes back to the middle of the river for the goose.

[BakedBeans]

The first thing is to bring the goose, because the fox won't eat the corn. Then bring the corn over and bring the goose back. Then bring the fox over,leave the goose and then get the goose ;)

[Thomas Veil]

I bow to your brilliance, sir. :D

[takao]

The first thing is to bring the goose, because the fox won't eat the corn. Then bring the corn over and bring the goose back. Then bring the fox over,leave the goose and then get the goose ;)

it's a classic in schools worldwide after all ;)

[jsw]

I suppose that "call FedEx" isn't an acceptible answer? Nor are "how would the goose open the bag of corn?" and "can't she tie up the fox?" allowed as questions.

Schools. Bah. So rigid in their required answers. ;) At least, since I was a child, they've changed the farmer to a "she".

[MongoTheGeek]

There is a slightly more complicated but similar one.
There are 4 people who need to cross a bridge. One takes 1 minute, the next 2 the next 3 and the last one 4 minutes. There are a few complications.

1) 2 people at a time in the bridge. (too weak to support more)
2) Its dark. Someone has to run a flashlight back so that more people can cross.
3) Crossing is done at the rate of the slowest person
4) 12 minute time limit or they are blown up/late for dinner.

[dotcomlarry]

I would have guessed you'd let the goose eat the corn, the let the fox eat the goose, and by doing that you get all three things across at once..... but oh well.

[jsw]

There is a slightly more complicated but similar one.
There are 4 people who need to cross a bridge. One takes 1 minute, the next 2 the next 3 and the last one 4 minutes. There are a few complications.

1) 2 people at a time in the bridge. (too weak to support more)
2) Its dark. Someone has to run a flashlight back so that more people can cross.
3) Crossing is done at the rate of the slowest person
4) 12 minute time limit or they are blown up/late for dinner.
Let #1 be the one that takes 1 minute, #2 the one takes 2 minutes, etc.

Send #1 & #4 over (4 min -> 4 min total)
Send #1 back (1 min -> 5 min total)
Send #1 & #3 over (3 min -> 8 min total)
Send #1 back (1 min -> 9 min total)
Send #1 & #2 over (2 min ->11 min total).

#1 always carries the flashlight.

What did I miss?

[medea]

No legs have I to dance,
No lungs have I to breathe,
No life have I to live or die
And yet I do all three.

What am I?

[takao]

No legs have I to dance,
No lungs have I to breathe,
No life have I to live or die
And yet I do all three.

What am I?

"flame" or "fire" would be my guess

[Wyvernspirit]

No legs have I to dance,
No lungs have I to breathe,
No life have I to live or die
And yet I do all three.

What am I?

Fire

[BakedBeans]

"flame" or "fire" would be my guess

bingo was his nameo

[Mr. Anderson]

My approach would have been to tie a rope to the goose and tow it along with you (they float, you know) and it would save you a trip.

D :D

[zarathustra]

My daughter was asked this riddle in a class in school. She gets extra credit if she gets it right.

A farmer has to get a fox, a goose, and a bag of corn across a river in a boat which is only large enough for her and one of these three items. She does not want to leave the fox alone with the goose nor the goose alone with the corn. How can she get all these items across the river?

Now: keep in mind that you must think of both sides of the river. The first solution that tends to come to mind is that she takes the goose across first. But if she comes back for either the fox or the corn, she'll have to leave one of those alone with the goose on the other side of the river. And that doesn't work.

The only solution that I can think of -- and it's not a truly satisfying one -- is the one below. I've made it a "spoiler" because I don't want to prejudice your thinking. You may not want to read it until after you've thought it through yourself, because frankly I think I'm going down the wrong road.

(Click-and-drag if you want to view: )



The farmer takes the goose first, leaves it in the middle of the river (it's a goose, remember?), then takes the fox across, then takes the corn across, and then comes back to the middle of the river for the goose.


I suppose this is a bit morbid:

Feed the corn to the goose. Feed the goose to the fox. Take the fox across the river.

[emw]

Schools. Bah. So rigid in their required answers. ;)

Yes, but at least now you can go home and have your parent ask 20,000 forum members for the answer. When I was a kid, we had to figure these things out on our own... ;)

[Doctor Q]

A bridge supports 150 pounds of weight. You weigh 148 and you are carrying three pieces of fruit that weigh a pound each. How do you get across in one trip carrying the fruit?

No, you don't eat the fruit and discard the peels, or take off your shoes, or some trick like that. You have to walk across with the fruit intact. I remember this puzzle and its solution from a puzzle book, although I never tried it myself.

[jsw]

A bridge supports 150 pounds of weight. You weigh 148 and you are carrying three pieces of fruit that weigh a pound each. How do you get across in one trip carrying the fruit?

No, you don't eat the fruit and discard the peels, or take off your shoes, or some trick like that. You have to walk across with the fruit intact. I remember this puzzle and its solution from a puzzle book, although I never tried it myself.Juggling - which I assume is the answer - won't work. The act of tossing the fruit will put the combined force above 150 pounds. You need to exert a force greater than one pound to heave a one pound piece of fruit into the air.

[emw]

A bridge supports 150 pounds of weight. You weigh 148 and you are carrying three pieces of fruit that weigh a pound each. How do you get across in one trip carrying the fruit?

No, you don't eat the fruit and discard the peels, or take off your shoes, or some trick like that. You have to walk across with the fruit intact. I remember this puzzle and its solution from a puzzle book, although I never tried it myself.

Well, I suppose if you really had to go to the bathroom that would help!

Actually, just juggle the fruit as you walk - you'd never be holding more than two at one time. At least as long as you're a good juggler.

Edit: Dammit. Should've skipped the funny stuff! :p

[emw]

Juggling - which I assume is the answer - won't work. The act of tossing the fruit will put the combined force above 150 pounds. You need to exert a force greater than one pound to heave a one pound piece of fruit into the air.

As evidenced by the fox/goose/corn riddle, reality seldom plays a role in these riddles...

[jtgotsjets]

A bridge supports 150 pounds of weight. You weigh 148 and you are carrying three pieces of fruit that weigh a pound each. How do you get across in one trip carrying the fruit?

No, you don't eat the fruit and discard the peels, or take off your shoes, or some trick like that. You have to walk across with the fruit intact. I remember this puzzle and its solution from a puzzle book, although I never tried it myself.

big fruit.

[Doctor Q]

Yeah, the answer is to juggle the fruit. But I decided not to try it myself since I couldn't find an appropriate about-to-collapse bridge. Now I'm glad!

[iLikeMyiMac]

Could you roll some of the fruit across and carry the rest. That way you only make 1 trip.

And what kind of POS bridge only holds 150lbs?

[Mr. Anderson]

Yeah, the answer is to juggle the fruit. But I decided not to try it myself since I couldn't find an appropriate about-to-collapse bridge. Now I'm glad!

Rolling would work, but throwing would too. Although it might get a bit messy.

Rigidity in the answers in not necessarily the case here. In general, the answers require out of the box thinking even though you can't be creative and come up with alternatives ;)

Good things for kids, look at the different perspectives.

D

[Les Kern]

I;m showing my age, but I remember that riddle from the early 70's
Here's a harder one from the 1500's:

A man dies, and he is taking the road to heaven. He comes upon a fork in the road; one leads to heaven, the other to hell. At the fork are twin brothers. Identical, except one ALWAYS tells the truth, the other ALWAYS lies. The man, who does not know which brother is which, gets to ask ONE brother ONE question. What is the question, and what path does he take?

[musicpyrite]

I;m showing my age, but I remember that riddle from the early 70's
Here's a harder one from the 1500's:

A man dies, and he is taking the road to heaven. He comes upon a fork in the road; one leads to heaven, the other to hell. At the fork are twin brothers. Identical, except one ALWAYS tells the truth, the other ALWAYS lies. The man, who does not know which brother is which, gets to ask ONE brother ONE question. What is the question, and what path does he take?

Ask the man that lies to tell him which way hell is, and then he takes that path.

[Doctor Q]

Ask the man that lies to tell him which way hell is, and then he takes that path.That won't work because he doesn't which man is the one that lies.

Instead, he should ask "Which way would your brother say is the road to heaven?" and take the other path.

Why it works:

If he had asked the truthful brother the way to heaven, he'd point out the correct way.

If he had asked the untruthful brother the way to heaven, he'd point out the wrong way.

If he asks the truthful brother "Which way would your brother say is the road to heaven", he will tell the truth, pointing the way his brother would, which is the wrong way.

If he asks the untruthful brother "Which way would your brother say is the road to heaven", he will lie, pointing the opposite of the way his brother would, i.e., the opposite of the right way, i.e., the wrong way.

So in either case the brother you ask will point the wrong way, and you know to go the other way.

[jimsowden]

Can anyone figure out the mathematical expression for that question?

[Doctor Q]

Here's my all-time favorite, adapted for present company:

A teacher asks three A students if they want to stay after school to try a brainteaser. They agree. One is a MacRumors member and the other two are not.

The teacher shows the students two kinds of stickers, Apple stickers and "Intel Inside" stickers, explaining that each student will get one or the other on their forehead. The teacher puts a sticker with an Apple logo on each student's forehead. None of the students know which sticker they got.

The teacher turns the students toward each other so they can each see the other two foreheads and tells whichever of them see at least one Apple sticker to raise their hand. All three raise their hand.

Finally, the teacher says they should keep their hand raised until they know which sticker they have on their forehead and can prove it logically.

All three students keep their hands up for a number of seconds. Then one hand lowers: the MacRumors member, who says "I have an Apple sticker on my forehead and I can prove it!"

How did the MacRumors member know and what is the proof?

[jsw]

Here's my all-time favorite, adapted for present company:

A teacher asks three A students if they want to stay after school to try a brainteaser. They agree. One is a MacRumors member and the other two are not.

The teacher shows the students two kinds of stickers, Apple stickers and "Intel Inside" stickers, explaining that each student will get one or the other on their forehead. The teacher puts a sticker with an Apple logo on each student's forehead. None of the students know which sticker they got.

The teacher turns the students toward each other so they can each see the other two foreheads and tells whichever of them see at least one Apple sticker to raise their hand. All three raise their hand.

Finally, the teacher says they should keep their hand raised until they know which sticker they have on their forehead and can prove it logically.

All three students keep their hands up for a number of seconds. Then one hand lowers: the MacRumors member, who says "I have an Apple sticker on my forehead and I can prove it!"

How did the MacRumors member know and what is the proof?
Tricky....

The reasoning of the MacRumors member must be something like this:

"If I had an 'Intel Inside' sticker on my forehead, then - aside from knowing due to the horrible burning sensation of having pure evil on my skin - each of the other two students would see one Apple and One 'Intel Inside' sticker. As a result, and knowing that the other student and I both raised our hands, each of those students would realize that they must have an Apple sticker, due to the fact that the other student saw one 'Intel Inside' sticker and still raised his hand. Since the other two students could not reach that conclusion, I must also have an Apple sticker on my forehead. Plus, I feel its healing aura."

[jsw]

A Mac user is presented with the following situation:

"You are outside a closed room with three lamps. On the wall in front of you are three switches - one for each lamp. You may manipulate the switches in any way you'd like prior to entering the room, but, upon opening the door, must be able to walk in and prove which switch controls which lamp without further altering the switches. Present your solution."

The Mac user quickly solved the problem. What was her solution?

[Doctor Q]

The reasoning of the MacRumors member must be something like this...Great work, jsw! Nice analysis.

It's interesting to note something that was necessary in the problem description: that they are all A students. We know that all MacRumors members are brilliant, but we needed to know that the other two were smart too, because otherwise they might not have been able to do the simple reasoning, and lowered their hands, if the MacRumors member hadn't had an Apple sticker. The MacRumors member had to count on that much intelligence from the other two in order to solve the problem.

You get 999 points for your answer, due to one minor quibble: You said "his hand". I didn't say if the students were male or female. :)

[jsw]

You get 999 points for your answer, due to one minor quibble: You said "his hand". I didn't say if the students were male or female. :)Only male students would be dumb enough to risk having an "Intel Inside" sticker stuck to their forehead. Hence, I concluded it must have been a "he".

[jimsowden]

A Mac user is presented with the following situation:

"You are outside a closed room with three lamps. On the wall in front of you are three switches - one for each lamp. You may manipulate the switches in any way you'd like prior to entering the room, but, upon opening the door, must be able to walk in and prove which switch controls which lamp without further altering the switches. Present your solution."

The Mac user quickly solved the problem. What was her solution?THe room is made of glass. Done and Done.

[jsw]

THe room is made of glass. Done and Done.Er, yes, points for that answer. Forgot to mention that the lamps are not viewable until the door is opened, and, once the door is opened, the switches cannot be altered. New solution?

[nerd]

A Mac user is presented with the following situation:

"You are outside a closed room with three lamps. On the wall in front of you are three switches - one for each lamp. You may manipulate the switches in any way you'd like prior to entering the room, but, upon opening the door, must be able to walk in and prove which switch controls which lamp without further altering the switches. Present your solution."

The Mac user quickly solved the problem. What was her solution?

This is a good puzzle. Here's my solution. It assumes that all the lamps have working light bulbs and that "on" is the "up" switch position. First, I turn on two of the switches and turn off the third. Then I take a break for a few minutes, maybe read some MacRumors articles. When I come back, I flip off one of the on switches, open the door and walk in the room. There should be one light on (corresponding to the on switch), one light off with a warm light bulb (corresponding to the switch I turned on for a while, then off), and one light off with a cool light bulb (corresponding to the switch that was off the whole time).

What do you think? Is there a better solution?

[jsw]

This is a good puzzle. Here's my solution. It assumes that all the lamps have working light bulbs and that "on" is the "up" switch position. First, I turn on two of the switches and turn off the third. Then I take a break for a few minutes, maybe read some MacRumors articles. When I come back, I flip off one of the on switches, open the door and walk in the room. There should be one light on (corresponding to the on switch), one light off with a warm light bulb (corresponding to the switch I turned on for a while, then off), and one light off with a cool light bulb (corresponding to the switch that was off the whole time).

What do you think? Is there a better solution?We have a winner! (partial credit went to the "glass walls" answer previously, as I had insufficiently described the problem).

[Les Kern]

That won't work because he doesn't which man is the one that lies.

Instead, he should ask "Which way would your brother say is the road to heaven?" and take the other path.

Why it works:

If he had asked the truthful brother the way to heaven, he'd point out the correct way.

If he had asked the untruthful brother the way to heaven, he'd point out the wrong way.

If he asks the truthful brother "Which way would your brother say is the road to heaven", he will tell the truth, pointing the way his brother would, which is the wrong way.

If he asks the untruthful brother "Which way would your brother say is the road to heaven", he will lie, pointing the opposite of the way his brother would, i.e., the opposite of the right way, i.e., the wrong way.

So in either case the brother you ask will point the wrong way, and you know to go the other way.

correct.

[scem0]

Can anyone figure out the mathematical expression for that question?

if x/truth = 1 and y/liar != 1 and you ask the numbers... ummm... this already doesn't sound very mathematical. I've tried asking numbers for answers many times during math tests, and the only thing I ever get is weird looks from fellow students.

Fancy that :cool:.

scem0

[Doctor Q]

The answer to this one made me laugh.

Question: What are the next two letters in the following series and why?

W A T N T L I T F S _ _

[iMeowbot]

Question: What are the next two letters in the following series and why?

W A T N T L I T F S _ _

Aw, I was going to explain initially, but then I changed my mind.

[homerjward]

A Mac user is presented with the following situation:

"You are outside a closed room with three lamps. On the wall in front of you are three switches - one for each lamp. You may manipulate the switches in any way you'd like prior to entering the room, but, upon opening the door, must be able to walk in and prove which switch controls which lamp without further altering the switches. Present your solution."

The Mac user quickly solved the problem. What was her solution?
simple. they were "lamp" g4 imacs next to pc all-in-ones with kvm switches and external monitors. the kvm switches were outside so she could manipulate them. she set one to a pc, one to an imac, and one to off. she could tell which was which by the keyboard and mouse cables (white on the imac black on the pc) she walked in and looked at the external monitors

[Doctor Q]

Aw, I was going to explain initially, but then I changed my mind.It's been a day. If you know the answer, you might as well tell us.

[iMeowbot]

It's been a day. If you know the answer, you might as well tell us.
Aw, I was going to explain initially, but then I changed my mind.

[rdowns]

The answer to this one made me laugh.

Question: What are the next two letters in the following series and why?

W A T N T L I T F S _ _

AW

First letter of each word in the question.

[MongoTheGeek]

Let #1 be the one that takes 1 minute, #2 the one takes 2 minutes, etc.

Send #1 & #4 over (4 min -> 4 min total)
Send #1 back (1 min -> 5 min total)
Send #1 & #3 over (3 min -> 8 min total)
Send #1 back (1 min -> 9 min total)
Send #1 & #2 over (2 min ->11 min total).

#1 always carries the flashlight.

What did I miss?

Its what I missed. I got the problem wrong. :( There is one set of number like that where that solution doesn't work.

Try 1,2,5,6 with a 14 minute limit.

[atszyman]

#1
Here's one I got in high school algebra. Handed it in as soon ans the teacher finished handing them out.

Two cars 20 miles apart start driving towards eachother at 20 miles/hour. After 1/2 hour they collide. As they are headed towards eachother there is a fly flying back and forth between the cars at 40 miles/hour. What is the total distance flown by the fly?

#2
My brother got this one once from a proffessor to disprove algebra.

Three people chip in $10 apiece to get a hotel room and order some pizza. The bill comes back and is only $25. They each decide to take $1 back and give the remaining $2 to the bellhop as a tip. Now each person has paid $9 for the room. $9*3 = $27 + $2 = $29. Where did the extra dollar go?

[emw]

#1
Here's one I got in high school algebra. Handed it in as soon ans the teacher finished handing them out.

Two cars 20 miles apart start driving towards eachother at 20 miles/hour. After 1/2 hour they collide. As they are headed towards eachother there is a fly flying back and forth between the cars at 40 miles/hour. What is the total distance flown by the fly?

20 miles (40 miles/hour * .5 hour = 20 miles)

#2
My brother got this one once from a proffessor to disprove algebra.

Three people chip in $10 apiece to get a hotel room and order some pizza. The bill comes back and is only $25. They each decide to take $1 back and give the remaining $2 to the bellhop as a tip. Now each person has paid $9 for the room. $9*3 = $27 + $2 = $29. Where did the extra dollar go?

As opposed to testing your math skills, it tests your reading skills. There is no extra dollar - they each paid $9. The total bill was $27 ($25 + $2) tip for the bellhop.

[Doctor Q]

20 miles (40 miles/hour * .5 hour = 20 miles)I read a book by Martin Gardner that told a story told about a famous scientist, but I forgot who, who was given this problem, solved it quickly and was then asked about the method used. He said he could have used the division method, as you did, but that he instead used the sum of the decreasing series of distances between the cars, because he found it was easier to compute! Anybody know which scientist it was?

In any case, that's the other way to solve the problem, for the brave at heart.

[Les Kern]

Three people chip in $10 apiece to get a hotel room and order some pizza. The bill comes back and is only $25. They each decide to take $1 back and give the remaining $2 to the bellhop as a tip. Now each person has paid $9 for the room. $9*3 = $27 + $2 = $29. Where did the extra dollar go?

The bellhop stole it because 2 bucks is one lousy tip.

[ejb190]

This is my favorite lateral thinking puzzle!

A man was found murdered in a room. In the room were a table, four chairs, and 53 Bicycles. What happened?

[Doctor Q]

This is my favorite lateral thinking puzzle!

A man was found murdered in a room. In the room were a table, four chairs, and 53 Bicycles. What happened?He was killed for cheating at cards.

http://www.magicpresto.com/jumbikes.JPG