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How old am I?
02-12-2018, 05:17 AM (This post was last modified: 02-12-2018 05:23 AM by Paul Dale.)
Post: #1
How old am I?
It's my birthday today.

This is the second time that my age has ended with its current digit and hasn't been prime. This will never happen again.

How old am I?

Kudos for doing this mentally like I did.
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02-12-2018, 07:53 AM
Post: #2
RE: How old am I?
(02-12-2018 05:17 AM)Paul Dale Wrote:  It's my birthday today.

This is the second time that my age has ended with its current digit and hasn't been prime. This will never happen again.

How old am I?

Kudos for doing this mentally like I did.

Now I know you are 57

Happy birthday!

Bernhard

That's one small step for a man - one giant leap for mankind.
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02-12-2018, 08:16 AM
Post: #3
RE: How old am I?
And I worked it out wrong Sad

Second last time .....


Sigh, old age is getting to me.


Pauli
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02-12-2018, 08:40 AM (This post was last modified: 02-12-2018 08:42 AM by Harald.)
Post: #4
RE: How old am I?
(02-12-2018 08:16 AM)Paul Dale Wrote:  And I worked it out wrong Sad

Second last time .....


Sigh, old age is getting to me.


Pauli

I don't get it. Have you got plans not to live beyond a certain age?

Oh, and happy birthday!
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02-12-2018, 08:55 AM
Post: #5
RE: How old am I?
It is just that I made a mistake in my calculation and didn't realise it was the second last time this will occur not the last.


Pauli
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02-12-2018, 09:11 AM
Post: #6
RE: How old am I?
(02-12-2018 08:55 AM)Paul Dale Wrote:  It is just that I made a mistake in my calculation and didn't realise it was the second last time this will occur not the last.


Pauli

I can't think of any digit that will cause all but three numbers to be prime if they end in this digit.

I am sat in the doctors waiting room with a high temperature, so maybe that excuses my ignorance...
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02-12-2018, 09:23 AM (This post was last modified: 02-12-2018 11:05 AM by Dieter.)
Post: #7
RE: How old am I?
(02-12-2018 08:55 AM)Paul Dale Wrote:  It is just that I made a mistake in my calculation and didn't realise it was the second last time this will occur not the last.

First of all: Happy birthday, Pauli! :-)
I hope you have a nice day and it's substantially warmer in Australian summer than over here on the Northern hemisphere.

But after your correction I still don't get how to determine your age.

"This is the second last time that my age has ended with its current digit and hasn't been prime. So it will happen only once again.", i.e. it happened an unknown number of times before (maybe never) and will happen exactly once in the future.

Or is it

"This is the second time that my age has ended with its current digit and hasn't been prime. Also this will happen only once again.", i.e. this happens exactly three times: once in the past, once now and once in the future.

?!?

If the latter version is correct the mystery digit is 3. The first time your age was not prime at an age of 33, now you are 63 and the next time this will happen at 93. After this the next non-prime age will be 123. Of course you may get that old, but... ;-)

Dieter

Edit: corrected a few typos.
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02-12-2018, 09:40 AM
Post: #8
RE: How old am I?
My guess: 63.

Happy birthday, Pauli, and thank you and your co-workers for the great WP34s, which keeps the spirit of our beloved calculators alive!

Andreas
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02-12-2018, 10:11 AM (This post was last modified: 02-12-2018 10:16 AM by Paul Dale.)
Post: #9
RE: How old am I?
Dieter,

Your first version is correct with the caveat that the last digit isn't constant. Of course, assuming I'm thinking straighter now Smile [edit: I'm not thinking straight, it's the third last time. It is amazing how badly I posed this Sad]


Yes, I had a great weekend in the rainforest doing a little bushwalking and generally relaxing.
It is a lot warmer here than wintery Europe I suspect. We only managed a half day walk yesterday because the forecast was a modest 38℃. Today was forecast to be higher, it felt about the same. The next two days are supposed to heat up some more.


Pauli
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02-12-2018, 10:14 AM
Post: #10
RE: How old am I?
Andreas,

Thanks!


Pauli
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02-12-2018, 10:17 AM
Post: #11
RE: How old am I?
(02-12-2018 05:17 AM)Paul Dale Wrote:  It's my birthday today.
...
How old am I?

I don't know, but *Happy Birthday*! Smile

Salvo

∫aL√0mic (IT9CLU), HP Prime 50g 41CX 71b 42s 12C 15C - DM42 WP34s :: Prime Soft. Lib
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02-12-2018, 10:30 AM
Post: #12
RE: How old am I?
(02-12-2018 10:11 AM)Paul Dale Wrote:  Your first version is correct with the caveat that the last digit isn't constant. Of course, assuming I'm thinking straighter now Smile [edit: I'm not thinking straight, it's the third last time. It is amazing how badly I posed this Sad]

OK, what about a final and correct version then ?-)
We still don't have a result that has been confirmed as correct.

(02-12-2018 10:11 AM)Paul Dale Wrote:  It is a lot warmer here than wintery Europe I suspect. We only managed a half day walk yesterday because the forecast was a modest 38℃.

Well, over here it's more like 38 °F. #-)

Dieter
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02-12-2018, 10:52 AM
Post: #13
RE: How old am I?
It's my birthday today.

This is the eighth time that my age has ended with its current digit and hasn't been prime.

How old am I?


It isn't as neat as I'd hoped Sad
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02-12-2018, 11:15 AM (This post was last modified: 02-12-2018 11:18 AM by Dieter.)
Post: #14
RE: How old am I?
(02-12-2018 10:52 AM)Paul Dale Wrote:  This is the eighth time that my age has ended with its current digit

So there are seven earlier occurences where the last digit of you age was the same as now. This means your age is > 70 and ≤ 80.

(02-12-2018 10:52 AM)Paul Dale Wrote:  and hasn't been prime.

This applies to all even ages except 72 (since 2 is prime). So you may be 74, 76, 78 or 80 now.

(02-12-2018 10:52 AM)Paul Dale Wrote:  How old am I?

I still don't know. But maybe there is something I didn't understand correctly.

Dieter
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02-12-2018, 03:15 PM
Post: #15
RE: How old am I?
A bit late & trusting you're still around, Happy Bday!

My guess is you're immortal.
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02-12-2018, 03:24 PM
Post: #16
RE: How old am I?
Difficult question this, but I must ask for clarity.

Do you start counting at zero or one?

Would you include zero years-old as age before 1st bday?

(Note awkwardness of English - "zero years-old".

"years" isn't the plural, it's the non-singular.)
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02-12-2018, 05:47 PM
Post: #17
RE: How old am I?
Happy Anniversary of your Birth!
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02-12-2018, 08:12 PM
Post: #18
RE: How old am I?
Happy 21st birthday! (In a prime base, but that’s just a detail :-)

That’s my guess because 11*5 + 8 = 63.

Gerson.
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02-12-2018, 08:47 PM
Post: #19
RE: How old am I?
It seems I can't get the wording correct. Oh well. Fifty one yesterday but ever so slightly older today. But none the wiser.


Pauli
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02-12-2018, 09:00 PM
Post: #20
RE: How old am I?
(02-12-2018 08:47 PM)Paul Dale Wrote:  It seems I can't get the wording correct. Oh well. Fifty one yesterday but ever so slightly older today. But none the wiser.


Pauli

Happy 51st birthday.

Now, had you been born in 1968 (the year I graduated high school) instead of 1967, and on Feb. 29, how many birthdays would you have had? You'd be a lot younger!
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