Thursday, March 15, 2012

Google Interview (2)

How many degrees are there in the angle between the hour and minute hands of a clock when the time is a quarter past three?

The stupid and quick answer would be 0 degree.

But, if we rethink again, it's not the case exactly.  When the minute  hand points to '15' (quarter), the hour hand has moved little bit.  How many? Let's analyze!

To make a full-circle (360 degrees rotation), the hour hand has to pass 12 hours, thus for one hour, it takes 360 degrees/12 = 30 degrees.  For a quarter hour = 1/4 * 30 = 7.5 degrees.

So the answer is: 7.5 degrees.

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