Love this thread!
My odds-
20% chance you bury the Bismarck
30% it's some sort of scam
49% she's a nice girl who wants to hang out.
(This could eventually lead to something)
1% chance she was born to swallow your seed
I think most guys here would be very happy for you if you hook up and she turned out to be a fun girl.
20%! That sounds high for any exchange of numbers, much less with the age gap. I think there's always the possibility of this being a scam, but given she knew the formula for standard deviation (highly unlikely for a girl running a scam), that he led the way (tho I acknowledge that's what scammers would want the guy to think), that they'd invest the time and energy to pull this act and then meet him for who knows how many times, makes me think it's just a new girl to the city who was grateful for the help, and caught off guard when he asked to meet up and now feels obliged to do it. Where Rongetcha takes it from there, is up to him.
If I was forced to come up with a conspiracy theory, then I would say it would have to be a targeted scam played for the long game, where they knew of Rongetcha's professional knowledge and boned up on investment and risk management lingo, knew he was likely to stray, and thought they could get enough out of him to play a much longer game than snatching a few hundred bucks off of him...most likely extortion to keep it secret from his wife or by his wife herself. Having said that....highly unlikely.
20% of banging from any girl you get digits from is high, but I think it'll be a fun adventure regardless...enjoy!