How old am I?

[Dieter]

(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.