One exceptionally pleasant day a mathematician, a physicist and a biologist decided to lunch at a nearby sidewalk café. As they sat eating, they observed the people coming and going around them. They watched as across the street one person, then another entered a building. A few minutes later, the two original people left in the company of a third.

"Did you see that?" said the biologist, "They reproduced!."
"Don't be silly.", said the physicist, "There was clearly a measurement error."
"You are both very funny.", said the mathematician, "It's obvious that if exactly one more person enters that building it will be empty."

 

Ho ho! One of my favorites!

 

"It's obvious that if exactly one more person enters that building it will be empty."

I don't get it; can you add a spoiler tag with an explanation?

 

I don't get it; can you add a spoiler tag with an explanation?

If you assume the initial contends of the building is zero, two people enter and three people leave, the number of people in the building is now -1. This is only possible in the abstract world of Mathematics.

 

If you assume the initial contends of the building is zero, two people enter and three people leave, the number of people in the building is now -1. This is only possible in the abstract world of Mathematics.

Ah, thank you for the explanation. I'm disappointed with the joke as it never occurred to me to assume that the building was initially empty.

 

Here's my favorite engineering joke, if you haven't seen it.

 

This is the sort of joke that makes you laugh three times: when you first read it, when it's explained to you, and when you finally get it...

 

If you assume the initial contends of the building is zero, two people enter and three people leave, the number of people in the building is now -1. This is only possible in the abstract world of Mathematics.

I thought it was zero base numbering, therefor we have 2 people leave in the company of a third. Still leaving -1, third person forgot his keys went back in as the door locks behind him, now zero again, poor bugger he has to wait for someone to open the door again

kv

 

I thought it was zero base numbering, therefor we have 2 people leave in the company of a third. Still leaving -1, third person forgot his keys went back in as the door locks behind him, now zero again, poor bugger he has to wait for someone to open the door again

kv

Which begs the question... how were the aforementioned building's stories numbered? ... was the floor immediately above ground assigned the number one, or number two?

 

Ah, thank you for the explanation. I'm disappointed with the joke as it never occurred to me to assume that the building was initially empty.

Ah, but mathematically, it’s the only assumption that makes sense. How appropriate!

 

Which begs the question... how were the aforementioned building's stories numbered? ... was the floor immediately above ground assigned the number one, or number two?

At one particular hotel in Las Vegas the floor above the Lobby is #14. It is true that the lobby has a high ceiling.

 

At one particular hotel in Las Vegas the floor above the Lobby is #14. It is true that the lobby has a high ceiling.

Lucky for everyone... floor numbering didn't start at #13 ...

 

You're right it may have been intentional in a gambling mecca as a way to sidestep the unluckiest of numbers. It is curious that it is on the wheel (roulette) however,

 

If memory serves me right, there are a few buildings in the world that deliberately skip the 13th floor.

Sometimes there's a gap in the structure itself, and sometimes said number is conspicuously absent with no apparent architectural cause.

 

Sometimes there's a gap in the structure itself

So levitation is relied on to support floor 14 and above?

 

So levitation is relied on to support floor 14 and above?

No. Look for the chains.

And sorry, stairs not available yet.

 

If memory serves me right, there are a few buildings in the world that deliberately skip the 13th floor.

Sometimes there's a gap in the structure itself, and sometimes said number is conspicuously absent with no apparent architectural cause.

It's old thread, but here goes.

We just stayed at the Four Seasons in Sydney Australia (this VERY nice 5-star hotel was cheaper than 2-star hotels in Honolulu, so we decided to splurge -- plus it was within easy walking distance of the Syndey Opera House where our daughter was performing). I noticed that the elevators had no floors 4, 5, or 13. I know that 13 is unlucky in a lot of places and that 4 is unlucky in most Chinese-speaking regions (and Australia has a significant Asian population), but neither my wife or I were aware of any place where 5 is unlucky. So I asked the Concierge and she said that 4 and 5 do exist, but they are admin, maintenance, and services (such as laundry), but that 13 is simply skipped because of the unlucky association.

By the same token, at the first hotel we stayed at in Honolulu, we were on the 13th floor.

An unrelated thing that amazed me about the Four Seasons -- the elevators really moved! We were on the 12th floor and from door close to door open it was four seconds, yet so smooth that you had a hard time feeling any motion or acceleration.

 

It's old thread, but here goes.

We just stayed at the Four Seasons in Sydney Australia (this VERY nice 5-star hotel was cheaper than 2-star hotels in Honolulu, so we decided to splurge -- plus it was within easy walking distance of the Syndey Opera House where our daughter was performing). I noticed that the elevators had no floors 4, 5, or 13. I know that 13 is unlucky in a lot of places and that 4 is unlucky in most Chinese-speaking regions (and Australia has a significant Asian population), but neither my wife or I were aware of any place where 5 is unlucky. So I asked the Concierge and she said that 4 and 5 do exist, but they are admin, maintenance, and services (such as laundry), but that 13 is simply skipped because of the unlucky association.

By the same token, at the first hotel we stayed at in Honolulu, we were on the 13th floor.

An unrelated thing that amazed me about the Four Seasons -- the elevators really moved! We were on the 12th floor and from door close to door open it was four seconds, yet so smooth that you had a hard time feeling any motion or acceleration.

No 13th here at embassy suites on Waikiki.

Numbers are an abstraction that doesn't seen to affect drunks.

 

Ah, thank you for the explanation. I'm disappointed with the joke as it never occurred to me to assume that the building was initially empty.

But isn't a building with a negative number of people in it empty?

Or is it that if there are more people than chairs it's N-type, and if there are more chairs than people it's P-type?

 

But isn't a building with a negative number of people in it empty?

Or is it that if there are more people than chairs it's N-type, and if there are more chairs than people it's P-type?

That would depend on how you define “empty”.

It could be that a negative person (less than 0 people) is something in it, making it not empty. I don’t know which polarity of charge a person is, though. If old Ben wrote about this then a “positive person”, that is, one signed + would be negatively charged.