[ghaff]

Yes. Give someone an hour, of course. I'd expect any minimally educated white collar professional to be able to that without a calculator.

As a verbal problem to answer in ten seconds? I'm more sympathetic with people freezing even if I certainly expect I'd be able to do it absent extreme pressure.

[WalterBright]

If someone regards an interview question as extreme pressure, I don't know what to say. Except advise the person to do more job interviews until they get used to it.