Fine then, now you can see our point of view of confusion on this..:
A man has a clock that chimes once for every hour at the top of the hour-- for example, at 6 o'clock, the clock chimes six times. It also chimes once on the half-hour.
He returns home in time to hear the clock chime once. A half-hour later, it chimes once. A half-hour after that, it again chimes, just once. Again, a half-hour later, it chimes just once. Finally, as he's leaving, he hears it chime, but just once.
What time was it when he first came home?