Biomedical Engineer Phd Interview Question:

Usually, if the answer to a brainteaser seems too easy, chances are the answer's wrong. And in this case, the answer is not zero degrees. The hour hand, remember, moves as well. That is, in addition to the minute hand. And so, at 3:15, the hour hand and the minute hand are not on top of each other. In fact, the hour hand has moved a quarter of the way between the 3 and 4. This means it's moved a quarter of 30 degrees (360 degrees divided by 12 equals 30). So the answer, to be exact, is seven and a half degrees (30 divided by four).