Can you solve the maths question for Singapore schoolkids that went viral?

[John Wright]

9 hours ago, Chinahand said:

I had heard this and it is amazing. Now I’ll defer to those with greater expertise but I do think the probability of these three oldies all having the luxury of being born on the same specific day - ie the day which results them being the oldest people in the world is one in 50 million which is quite different affair than 3 people being born on a general day only special because granny was born on that particular day - ie one of the 3. 

The odds of people having the same birthday in 1908 must be very high. Let’s say, UK  wide 20,000 were born on that day it’s then an actuarial calculation. Worldwide it may have been a 500,000 born on that day. Of course the mortality rates and actuarial tables for different birth locations would be wildly different.

[Uhtred]

A former colleague of mine celebrated his birthday on 26th October. His grandmother, mother, brother and sister were all born on 26th October, though of course in different years.

[Chinahand]

Oh, crap.  John Conway has been taken by Covid-19.

The Game of Life is a wonderful thing - even the simplest of rules can create turing machines.  XKCD has a wonderful obituary:

Edited April 13, 2020 by Chinahand

[Chinahand]

On 2/15/2020 at 2:24 PM, Chinahand said:

In celebration of Doug Hofstadter's 75th birthday - do read Godel, Escher and Bach it is awesomely thought provoking, I present the following paradox:

How many errors do you see in the sentence below?
"This sentense has three erors."

 

Similar -

 

[Declan]

That's hurting my brain...

1 in 4 = 25%

So A + D are correct so that's 2/4 = 50%

So C is correct but that's 1 out 4 = 25%

So A + D are correct so that's 2/4 = 50%

And so on - that must mean that there's no right answer, and if there's no right answer the answer is 0% which is B.

So B is correct because there's no correct answer, but that's 1 out 4 = 25%

So A + D are correct so that's 2/4 = 50%

So C is correct but that's 1 out 4 = 25%

So A + D are correct so that's 2/4 = 50%

And so on - that must mean that there's no right answer, and if there's no right answer the answer is 0% which is B.

But nobody would guess that 0% was right anyway because there's always a correct  answer on Who Want's To Be A Millionaire? So you are going to guess A, C or D and then you have a 33% chance of being right but that isn't one of the answers. So you've a 0% of guessing right.

Which is B and because you're never going to guess B because there's always a correct answer and we've just established that there is a correct answer - "B" but you are never going to guess it.

Can I phone a friend?

[wrighty]

6 hours ago, Declan said:

That's hurting my brain...

1 in 4 = 25%

So A + D are correct so that's 2/4 = 50%

So C is correct but that's 1 out 4 = 25%

So A + D are correct so that's 2/4 = 50%

And so on - that must mean that there's no right answer, and if there's no right answer the answer is 0% which is B.

So B is correct because there's no correct answer, but that's 1 out 4 = 25%

So A + D are correct so that's 2/4 = 50%

So C is correct but that's 1 out 4 = 25%

So A + D are correct so that's 2/4 = 50%

And so on - that must mean that there's no right answer, and if there's no right answer the answer is 0% which is B.

But nobody would guess that 0% was right anyway because there's always a correct  answer on Who Want's To Be A Millionaire? So you are going to guess A, C or D and then you have a 33% chance of being right but that isn't one of the answers. So you've a 0% of guessing right.

Which is B and because you're never going to guess B because there's always a correct answer and we've just established that there is a correct answer - "B" but you are never going to guess it.

Can I phone a friend?

I’d suggest you choose Kurt Godel

If you’re not familiar with his famous incompleteness theorem then look it up. That’ll really blow your mind. 

[Chinahand]

This one took me a while, but by applying the Feynman method I got it!

 

[wrighty]

2 hours ago, Chinahand said:

This one took me a while, but by applying the Feynman method I got it!

 

Feynman method? Summing the path integrals???

I used a combination of Pythagoras and similar triangles 

[Chinahand]

https://www.jurnalanas.com/feynman-and-the-art-of-problem-solving/#:~:text=The Feynman Algorithm%3A,Write down the solution.

😉

😉

[wrighty]

31 minutes ago, Chinahand said:

https://www.jurnalanas.com/feynman-and-the-art-of-problem-solving/#:~:text=The Feynman Algorithm%3A,Write down the solution.

😉

😉

Fair enough.  I couldn’t really see how this would have helped. 

[display name]

On 4/13/2020 at 11:07 PM, Chinahand said:

Oh, crap.  John Conway has been taken by Covid-19.

It didn't work out for him then

[Chinahand]

https://www.theguardian.com/science/series/alex-bellos-monday-puzzle

 

 

[wrighty]

1 hour ago, Chinahand said:

https://www.theguardian.com/science/series/alex-bellos-monday-puzzle

 

 

24.  Working provided on request.

[Chinahand]

Got the same. 🙂

A hint: the digits 5 & 8 recur in digging for the answer. 

[wrighty]

24 minutes ago, Chinahand said:

Got the same. 🙂

A hint: the digits 5 & 8 recur in digging for the answer. 

I just counted the number of 5s in the prime decomposition of 100! safe that there are more than enough 2s to make all the 10s.  Not forgetting the doubled up factors in 25, 50, 75 and 100, obviously.