A person travels on the surface of an equilateral triangle at speeds of 12kmph, 8kmph and 6kmph. Find the average speed of the entire journey. (In Kmph)

A cyclist covers his first 20 km at an average speed of 40 kmph, another 10 km at an average speed of 10 kmph and the last 30 km at an average speed of 40 kmph. Then the average speed of the entire journey is

Gautam goes to office at a speed of 12 kmph and returns home at 10 kmph. His average speed is :

A car moves from A to B with a speed of 30 kmph and from B to A with a speed of 20 kmph. What is the average speed of the car ?