Question

a car travels first 30 km with a uniform speed of 60 km per hour and then next 30 km with a uniform speed of 40 km per hour calculate the total time of a journey the average speed of a car

Answer 1

for first 30 km ,time=D/S=30/60=1/2 hour or 30 min

for next 30 km ,time=D/S=30/40=3/4 hour or 75 min

total time =(75+30)min=105min or 1h45min