I answered this question recently, so I wanted to contribute back to this forum with the correct answer. It's not as simple as you might think. I was asked what the difference was between the two hands at 9:30. On the surface, you might say (1/4)*360 = 90 degrees, but you have to remember that the hour hand moves gradually. Therefore, at 9:30, the hour hand is actually halfway between 9 and 10. Thus, you have to add 15 degrees onto it to get 105 degrees.