Originally Posted by

**kevinm** I have no idea how to start with this problem. I have the general outline but I do not know how to solve it. By general outline I mean the sketch of the problem.

**A lighthouse is located on a small island 3 km away from the nearest point P on a straight shoreline and its light makes four revolutions per minute. How fast is the beam of light moving along the shoreline when its 1km from P?**

If anyone can help on how to go about this problem it would be much appreciated. Thanks in advance.