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PhDemon
Post  Post subject: Brainteasers  |  Posted: Tue Mar 14, 2017 2:03 pm

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Here are some lateral thinking brainteasers I set my classes this week... Have a go see how you get on!

A bear walks south for one kilometer, then it walks west for one kilometer and then north for one kilometer and ends up at the same point it started. What colour was the bear?


You have to measure exactly 4 litres of water but you only have a 3 litre bottle and a 5 litre bottle. How do you do it?


When I'm young I'm tall, when I'm old I'm short. When I'm alive I glow. Because of your breath I die. What am I?

Post your answers in a suitable colour so that they have to be highlighted to be visible so you don't give the game away if you solve them!

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geordief
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 2:48 pm

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How much self restraint do your students have? I could not get the answers but they are only 2 or 3 clicks away on a computer.(perhaps harder on a smart phone)


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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 2:52 pm

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They aren't allowed to cheat.. no mobile devices in class!

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geordief
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 3:08 pm

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PhDemon wrote:
They aren't allowed to cheat.. no mobile devices in class!

Oh, I thought it was homework :oops:


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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 3:34 pm
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PhDemon wrote:
Here are some lateral thinking brainteasers I set my classes this week... Have a go see how you get on!

A bear walks south for one kilometer, then it walks west for one kilometer and then north for one kilometer and ends up at the same point it started. What colour was the bear?


You have to measure exactly 4 litres of water but you only have a 3 litre bottle and a 5 litre bottle. How do you do it?


When I'm young I'm tall, when I'm old I'm short. When I'm alive I glow. Because of your breath I die. What am I?

Post your answers in a suitable colour so that they have to be highlighted to be visible so you don't give the game away if you solve them!


1- white. I don't Know how to explain but it's becauce it's the north pole. :lol: :lol: :lol:

2- I use 2 x 5 L bottle and 2 x 3 L bottle. I put 5L in each 5L bottle and then "transfer" water to fill the 3 L bottles. So I have 2 L left in each 5 L bottle. Then I mix the two bottles in one to get the 4L.

It doesn't say that you only have one bottle of each, it only says that you only have those types of bottles.

3- I have no idea :mrgreen: .


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geordief
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 3:42 pm

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M_Gabriela wrote:



2- I use 2 x 5 L bottle and 2 x 3 L bottle. I put 5L in each 5L bottle and then "transfer" water to fill the 3 L bottles. So I have 2 L left in each 5 L bottle. Then I mix the two bottles in one to get the 4L.

It doesn't say that you only have one bottle of each, it only says that you only have those types of bottles.



Yes it does say one bottle of each


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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 3:45 pm
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Ok then:

I fill a container with 15 L of liquid (using the 5L bottle). Then I use the 3 L bottle and I take 6 L of water. Then I use the 5L bottle and take 5 more L of liquid. Then I have 4 L left in the container.


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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 4:12 pm

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Your answer to number 1 is correct...

You don't have a 15 L container...

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geordief
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 4:14 pm

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M_Gabriela wrote:
Ok then:

I fill a container with 15 L of liquid (using the 5L bottle). Then I use the 3 L bottle and I take 6 L of water. Then I use the 5L bottle and take 5 more L of liquid. Then I have 4 L left in the container.

I don't think you are allowed to use an extra container. Just the 2 bottles.


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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 4:16 pm

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Yep that's right, there are at least two ways to do it using just one 3 L bottle and one 5 L bottle...

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DrKrettin
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 4:20 pm
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M_Gabriela wrote:

1- white. I don't Know how to explain but it's becauce it's the north pole. :lol: :lol: :lol:



1- whiteThe North Pole is only one point solution, there are an infinite number of solutions near the South Pole. If the distance walked westwards is exactly equal to the circumference of a circle around the South Pole, then the starting point could be anywhere on a latitude very near that pole. However, there are no bears there. Therefore.....


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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 4:43 pm
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DrKrettin wrote:
M_Gabriela wrote:

1- white. I don't Know how to explain but it's becauce it's the north pole. :lol: :lol: :lol:



1- whiteThe North Pole is only one point solution, there are an infinite number of solutions near the South Pole. If the distance walked westwards is exactly equal to the circumference of a circle around the South Pole, then the starting point could be anywhere on a latitude very near that pole. However, there are no bears there. Therefore.....


Exactly. That's why the solution is only north pole.


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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 4:44 pm
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Are the bottles graduated?

EDIT: no forget it. It would be very simple that way


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DrKrettin
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 4:49 pm
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M_Gabriela wrote:
DrKrettin wrote:
M_Gabriela wrote:

1- white. I don't Know how to explain but it's becauce it's the north pole. :lol: :lol: :lol:



1- whiteThe North Pole is only one point solution, there are an infinite number of solutions near the South Pole. If the distance walked westwards is exactly equal to the circumference of a circle around the South Pole, then the starting point could be anywhere on a latitude very near that pole. However, there are no bears there. Therefore.....


Exactly. That's why the solution is only north pole.


I had not realised that you had actually given an answer - I thought the reference to a colour was in connection with the text of your answer. Duh. :lol:


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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 4:55 pm
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Jaaaaa.

So my colleague found the answer for the last two. I've been thinking the two problems for the last hour and she gave me the answer in less than 10 seconds.....

Pathetic... I have no lateral thinking at all... :lol: :lol: :lol: :lol: :lol: :lol:


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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 5:17 pm

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Don't feel too bad.. In the class some students couldn't solve any of them and only one student got all three in the 10 minute time limit.

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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 5:23 pm
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:roll:

But I'm 31 and have a university degree..


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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 5:25 pm

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Neither of which make you a lateral thinker... ;) Age and education aren't the point, you don't need advanced knowledge to solve them...

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marnixR
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 5:32 pm
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is no.3 a candle ?

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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 14, 2017 5:33 pm

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Yep, that's right.

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One beer
Post  Post subject: Re: Brainteasers  |  Posted: Wed Mar 15, 2017 2:03 pm
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Q1= White. (polar bear starting and finishing from the North Pole)
Q2 = fill the 5 litre jug then use that to fill the 3 litre jug. 2 litres will be left in the 5 litre jug which you pour into another jug then repeat. If you are not allowed a third container, then measure the weight of both empty jugs. Then the weight of full jugs. Now you know the density of the water which should be 1 kg/cubic litre, and also the weight of 8 litres. Then you can pour out water from the 5 litre jug until you have 4 kg/litres of water left?
Q3 = A candle.


Not sure about Q2

OB


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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Wed Mar 15, 2017 2:26 pm
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No. It is no that, for question 2. The worst part is that it is very simple. We really like to complicate things. As I said before I was humiliated by my 65 year old colleague who discovered the answer in less than 10 seconds.


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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Wed Mar 15, 2017 4:13 pm

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One beer wrote:
which you pour into another jug then repeat



You don't have another jug... As for the rest it's easier than that ;)

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One beer
Post  Post subject: Re: Brainteasers  |  Posted: Thu Mar 16, 2017 9:22 am
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Oh wait. Ha ha, I've got it :

You fill the 5l jug and then fill the 3l jug from that. Now you have 2l left in the 5l jug. Now empty the 3l jug and pour the 2l from the 5l jug into it. Then refill the 5l jug and top up the 3l jug from the 5l jug. You are left with 4l in the 5l jug !

Phew !

These are good. More please.

OB


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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Thu Mar 16, 2017 10:41 am

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Yep , that's one of the ways to do it.

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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 21, 2017 1:31 pm
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The other possibility for number 2 is (the one my colleague told me of course):

Half fill both bottles, that's how you get 4 L. 1.5 from the 3 L bottle and 2.5 from the 5 L bottle, that gives 4 L.


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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 21, 2017 2:39 pm

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M_Gabriela wrote:
The other possibility for number 2 is (the one my colleague told me of course):

Half fill both bottles, that's how you get 4 L. 1.5 from the 3 L bottle and 2.5 from the 5 L bottle, that gives 4 L.


Nope, that's not allowed. How do you know the bottles are exactly half full?

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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 21, 2017 2:57 pm
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:o :o :o :o :o :o :o


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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 21, 2017 3:04 pm
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I kinda feel good that she's wrong... hahahahahaha


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M_Gabriela
Post  Post subject: Re: Brainteasers  |  Posted: Tue Mar 21, 2017 10:51 pm
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Ok, got it:

Fill the 3L bottle and then pour it into the 5L bottle.
Fill the 3L bottle again and pour it in the 5L Jarr. There will be 1L left in the 3L bottle.
Then empty the 5L bottle. Pour the 1L liquid from the 3L bottle and then re fill the 3L bottle and pour it again in the 5L bottle. That will give 4L

!!!!
Sorry for my english... very difficult to write this


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iNow
Post  Post subject: Re: Brainteasers  |  Posted: Wed Mar 22, 2017 12:13 am
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Your English is fine :D

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iNow

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PhDemon
Post  Post subject: Re: Brainteasers  |  Posted: Wed Mar 22, 2017 8:04 am

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Yep Gabriela, that's the second way to do it...

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