Question

A car travels 30km at a uniform speed of 40 km/h and next 30km at a uniform speed of 20 km/h. Find its average speed.

Answer 1

Total distance travelled = 60 km

Time for which it travels the first 30 km at speed 40 km/h is = 30/40 = 3/4 h

Time for which it travels the next 30 km at speed 20 km/h is = 30/20 = 3/2 h

So, total time of travel is = 3/4 +3/2 = 9/4 h

Average speed is = 60/9/4 = 240/9 = 26.67 km/h