<s>[INST] The distance between the palaces of the two kings is 72 miles. Each king has one advisor who is waiting for the the king to arrive. The advisors decide that they want to meet at a point that is halfway between the two palaces to discuss something.

If one advisor starts walking at 4 mph and the other advisor starts walking at 5 mph, how much time will it take for the two advisors to meet?[/INST]