Comment by Flenser
5 months ago
I thought you were wrong so I went googling and someone did the experiment and you are correct. Option 2, adding the milk later, cools fastest: https://www.thenakedscientists.com/get-naked/experiments/whe...
The graph on that page explains it much better than any of the text explanations can.
There are two subtleties here that MBA/Finance bros always miss out on brain teasers. First subtle point is that it makes no difference at all in which order you do the mixing, if additional cooling of milk for two minutes while it is still in the refrigerator is also taken into account, for the second option.
The other even more subtle point is that temp (unlike pressure) doesn't equilibrate instantaneously, as is assumed in the second option. It is a diffusive process which follows a complicated parabolic partial differential, equation, whose solution will determine the final temp of the tea+milk+partial adiabatic convection cooling of the cup. It took Fourier a detour through Complex numbers to figure it out.
I find all LLMs do quite well when presented with a well poised engineering/physics/chemistry problems with well defined parameters, including relativistic or second order effects. The confusion/hallucination is mostly imparted on them by user's lack of sophistication in articulation, or computational limitations.