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Maths Riddle

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I never saw this until today, but it seems to have been going the rounds for some years and generated a lot of discussion. Googling the first phrase gets over 2 million hits.

A man buys a horse for £60 and sells it for £70. He then repurchases for £80, and sells it for £90.

Has he gained or lost, if so by how much? Or has he broken even?

Sometimes it’s a goat or a pig etc.

Permalink 3 comments (latest comment by Jan Pinfield, Thursday, 2 Jun 2022, 18:48)
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Seating Puzzle Solution

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Edited by Richard Walker, Wednesday, 1 Jun 2022, 20:52
https://learn1.open.ac.uk/mod/oublog/viewpost.php?post=246698

9 students and 9 professors attend a dinner at which they sit at a round table. The organisers wish to arrange the seating so that no one is seated between two professors. Is this possible to meet this condition?

Solution: Imagine we have found an arrangement that meets the conditions. Ask every other person to stand up, so 9 people will be standing. Then we cannot have two professors separated by only a single seated person, otherwise that person would be flanked by professors. But this means only 4 of the 9 standing persons can be professors.

However the same reasoning can be applied to the 9 people who are sitting down, so we can only accommodate 8 professors altogether, leaving one professor unaccounted for.

Consequentially no arrangement can exist that meets the given condition.

Permalink 2 comments (latest comment by Richard Walker, Thursday, 2 Jun 2022, 12:26)
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Brrrrh

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Snow and ice

Isn’t nice.

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The Karma again

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At the Karma Restaurant we serve just desserts.


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Please be seated

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Edited by Richard Walker, Sunday, 29 May 2022, 23:44

9 students and 9 professors attend a dinner at which they sit at a round table. The organisers wish to arrange the seating so that no one is seated between two professors. Is this possible?


Permalink 8 comments (latest comment by Joseph McDonnell, Tuesday, 31 May 2022, 13:40)
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The Karma

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Edited by Richard Walker, Sunday, 5 Jun 2022, 22:09





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I asked for advice …

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Edited by Richard Walker, Sunday, 29 May 2022, 21:01

… and this is what I got 



Permalink 1 comment (latest comment by Joseph McDonnell, Monday, 30 May 2022, 06:18)
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One Liner🍦

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I managed to get an exclusive story about ice cream. It was a scoop.

Permalink 1 comment (latest comment by Joseph McDonnell, Saturday, 28 May 2022, 19:48)
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Growing Up

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Permalink 1 comment (latest comment by Jessica Shier, Saturday, 28 May 2022, 20:46)
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My Mate Joke

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My mate was very skinny. We called him Finn.

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Bar Joke

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Two herrings walked into a bar. Well, they got kippered.

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The Scourge Of The Seas

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A Village Sunset

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Edited by Richard Walker, Friday, 27 May 2022, 00:56


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Days of the Weak

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What follows Fryday? Fatterday.


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Dead Calm

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For several hours there has been almost no wind in my garden, the wind speed is effectively 0 km/h.

I think this must be quite unusual, although the Hairy Ball Theorem tells us that there must always be a point on the earth where the wind isn't blowing at any given moment.

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Viral

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Edited by Richard Walker, Sunday, 22 May 2022, 23:34

I had a nasty Gold. Azure I went. So I Blue by dose.

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A Cornish Sunset

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Lemon stampede

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Weather Report

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Permalink 2 comments (latest comment by Jessica Shier, Saturday, 28 May 2022, 20:47)
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Two codfish walked into a bar

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Well, they got battered.

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Dad Joke

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What do you call a man wearing two raincoats?

Max.

Permalink 2 comments (latest comment by Joseph McDonnell, Thursday, 19 May 2022, 15:23)
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Probability question

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Suppose three different numbers are chosen independently at random. What is the probability that the third lies between the first two?

Permalink 2 comments (latest comment by Richard Walker, Wednesday, 18 May 2022, 19:40)
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The pedant’s ice cube

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A regular hexahedron of dihydrogen monoxide in the solid phase.

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Goldfinch eating forget-me-nots

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Here's a rather impressive photo my brother took.



Permalink 2 comments (latest comment by Richard Walker, Monday, 23 May 2022, 20:48)
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Knock-knock

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Knock-knock!

    Who’s there.

Cher.

    Cher who?

Cher turn to do the washing up!

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