52 factorial - anyone else find it mind boggling

thedoswells

Well-known Member
I can’t really get my head around this.
i mean, I understand it, but it seems crazy.
a normal pack of cards, and the number of different ways the cards can be arranged.

Scott Czepiel has a good description of it, but the number of ways is:
80658175170943878571660636856403766975289505440883277824000000000000

maybe it’s just me.... :eek:
 

nheather

Distinguished Member
Can't say it surprises me - as you say it is 52! (the factorial of 52) so I would expect it to be a huge number.

I mean it is already up at 2652 when you have just picked the first two cards.

Cheers,

Nigel
 

Kailash

Member
what always surprised me was how few combinations 4 digits could be made into
i think it's 10,000 combinations using digits 0 - 9
so our card PIN numbers are not that secure for a hacker, i'm sure software could pulse through those in no time
 

DPinBucks

Distinguished Member
what always surprised me was how few combinations 4 digits could be made into
i think it's 10,000 combinations using digits 0 - 9
so our card PIN numbers are not that secure for a hacker, i'm sure software could pulse through those in no time
4-digit PINs are generally safe from that kind of attack. Their use is limited. On physical keypads such as ATMs, software like that doesn't apply. On digital devices, such as phones, they lock up after a few incorrect attempts.
 

DPinBucks

Distinguished Member
As a follow-up, this is an interesting article about so-called 'perfect hands' in bridge, which have been reported a few times in history despite the underlying odds against.

Perfect Bridge Hand

Note that the random odds against are far less than 52!, because it doesn't matter which order each suit comes in, only that they are always arranged H C D S, H C D S, etc
 

hippo99

Distinguished Member
what always surprised me was how few combinations 4 digits could be made into
i think it's 10,000 combinations using digits 0 - 9
so our card PIN numbers are not that secure for a hacker, i'm sure software could pulse through those in no time
You only get 3 incorrect attempts before your card is swallowed/blocked by the ATM/till.
 

nheather

Distinguished Member
The one that surprised me, when I heard it, not when I looked at the maths, is the chances that at least two people in group share a birthday (day and month, not year).

If you had a group of 23 people, without giving it much thought, you would guess that it is quite low but it is actually 50%.

At 30 people that rises to 70%

And at 40 people it is 90%

In reality the chances of a match are actually higher as real birthdays tend to be clustered rather than spread out evenly.

Cheers,

Nigel
 

DPinBucks

Distinguished Member
The one that surprised me, when I heard it, not when I looked at the maths, is the chances that at least two people in group share a birthday (day and month, not year).

If you had a group of 23 people, without giving it much thought, you would guess that it is quite low but it is actually 50%.

At 30 people that rises to 70%

And at 40 people it is 90%

In reality the chances of a match are actually higher as real birthdays tend to be clustered rather than spread out evenly.

Cheers,

Nigel
Years ago at a rather well-lubricated dinner party I made that claim, to some scepticism. There were only about 10 people there, but I thought it worth a go:

"OK", I said, "let's try it".

I turned to the guy on my left: "When's your birthday, then?"

"14th September".

My birthday is the 14th of September. End of demo.
 

The Dreamer

Distinguished Member
I was in a crew hotel in New York many years ago - there were just the 3 of us, the Captain, myself, and Stan, the barman. Stan was showing us a photo of his dad, who had been a waist gunner on B-29's in the Second World War. The date on the photo was 3rd October 1944.

'Just a day before my birthday' said Stan. To which my skipper said, 'That's a day before my birthday'. And to which I replied, 'You're not going to believe this!'

So, just 3 random people in the same room, and we all shared 4th October birthdays!


Slightly different, but....


Both of my boys share the same birthday, albeit 2 years apart. Annual shag!:blush:
 

imightbewrong

Distinguished Member
Years ago at a rather well-lubricated dinner party I made that claim, to some scepticism. There were only about 10 people there, but I thought it worth a go:

"OK", I said, "let's try it".

I turned to the guy on my left: "When's your birthday, then?"

"14th September".

My birthday is the 14th of September. End of demo.
Science - it works bitches
 

imightbewrong

Distinguished Member
Both of my boys share the same birthday, albeit 2 years apart. Annual shag!:blush:
Two of ours are one day apart - I haven't checked but I suspect a leap year threw us off.
 

imightbewrong

Distinguished Member
I can’t really get my head around this.
i mean, I understand it, but it seems crazy.
a normal pack of cards, and the number of different ways the cards can be arranged.

Scott Czepiel has a good description of it, but the number of ways is:
80658175170943878571660636856403766975289505440883277824000000000000

maybe it’s just me.... :eek:
You might also like

 

imightbewrong

Distinguished Member

DPinBucks

Distinguished Member
Everything has a 50/50 chance, it either is or it isn't :)
So that statement itself has a 50/50 chance of being true. Which means everything has a 50/50 chance of being 50/50. Which means everything has a 25% chance of being true, and a 25% chance of being false.

Which means ....
 

imightbewrong

Distinguished Member
Nope, it is still either true or not true, 50/50 ;)
I'm going to flip a coin to see if you are right - 50/50 - Tails - nope, sorry.
 

nheather

Distinguished Member
4-digit PINs are generally safe from that kind of attack. Their use is limited. On physical keypads such as ATMs, software like that doesn't apply. On digital devices, such as phones, they lock up after a few incorrect attempts.
Many of you have seen door locks like these

6015FE86-57AA-46DD-8A50-7D0093814BA2.jpeg


What you may not know is that they are not as good as they look.

Firstly, there is no lockout, so you get as many tries as you want.

Secondly, they are combination locks not permutation locks (interesting point - what are sold as combination locks are actually permutation locks) the difference is that with permutations the order matters. With these door locks the order doesn’t matter, so 2457, is exactly the same as 7254, and 5274 and so on. So not as many different codes as you would think. You also cant have duplicates numbers for this reason - so at setup, if you entered 7327 as your chosen PIN you would end up with a 3 digit PIN.

Thirdly, you can often tell what buttons have been pressed, worn, prints, grease marks etc. Combined with the second point, pretty easy to enter a code that will work.

Cheers,

Nigel
 
Last edited:

imightbewrong

Distinguished Member
Many of you have seen door locks like these

View attachment 1268381

What you may not know is that they are not as good as they look.

Firstly, there is no lockout, so you get as many tries as you want.

Secondly, they are combination locks not permutation locks (interesting point - what are sold as combination locks are actually permutation locks) the difference is that the order matters. With these door locks the order doesn’t matter, so 2457, is exactly the same as 7254, and 5274 and so on. So not as many different codes as you would think.

Thirdly, you can often tell what buttons have been pressed, worn, prints, grease marks etc. Combined with the second point, pretty easy to enter a code that will work.

Cheers,

Nigel
Also great for getting Coronavirus from.
 

imightbewrong

Distinguished Member

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