I would tell him to invest in a better time calculating device, I'm only assuming he uses a sun dial to tell time.

Really though I work in a parking garage and everything about my job involves time, you would be surprised at how many people pull up to the booth and say they have only been here for "5 minutes" when in fact most the time it's 20 or more minutes. So basically what I'm saying is I think that 80% of the general public can't judge elapsed time very well.