A man leaves P and reaches Q in 3 hours at an average speed of 60 kmph. The distance from P to Q is 180 km. The document discusses relationships between speed, time, and distance. It provides formulas for calculating speed, time, and distance when two of the variables are known. It also covers converting between units of speed and examples of problems calculating distance or time when given speed(s) and time(s) for parts of a journey.