Question

A car moves with a speed of 30km/hr for half an hour, 25km/hr for one hour and 40km/hr for 2 hours. Calculate the average speed of the car.

Answer 1

First half

v 1 = 30 km /hr

t 1 = 1/2 hr = 0.5 hr

d = v t = 30×0.5 = 15 km

Second half

V 2 = 40 km/hr

t 2 = 2 hr

d 2 = v t = 80 km

Average speed

= total distance / total time taken

= d 1 + d 2 / t 1 + t 2

= 80+ 15 / 2+0.5

= 95 /2.5

= 38 km/hr

Average speed = 38 km/hr