Time...

So, I'm sitting in a public place, sitting because I don't feel like doing anything else and these three teenagers end up standing next to me and one of them asks if I have a watch.

I thought about saying "Yeah" but instead I looked at my watch and said quarter past one. There was silence for a moment then one teenager asked another teenager "What does that mean?". The answer given by the one that originally asked was one forty five. So I said "Actually it's one fifteen, ...sorry".