Question

A car travels first 30 km at a uniform speed of 20km/hr and next 30 km at a uniform speed of 40km/hr. What is the average speed?

Answer 1

Here, Total distance travelled, S = 30 + 30 = 60 km

Time taken to travel first 30 km at speed 20 km/h is = 30/20 = 1.5 h

Time taken to travel next 30 km at 40 km/h is = 30/40 = 0.75 h

Average speed = total distance/total time = 60/(1.5+.75) = 60/2.25 = 26.67 km/h