A boat is pulled into a dock by means of a rope attached to a pulley on the dock. The rope is attached to the front of the boat, which is 9 feet below the level of the pulley. If the rope is pulled through the pulley at a rate of 10 ft/min, at what rate will the boat be approaching the dock when 120 ft of rope is out?

The boat will be approaching the dock at _____ ft/min.

Hint: Sketch a diagram of this situation.