Question

a car travels at 54km/hr for first 20 s, 36km/hr for next 30 s and finally 18 km/hr for next 10 s. Find its average speed.

Answer 1

Hey mate __

distance =speed *time

so , d=54*5/18 *20 = 15*20= 300 m
d = 36*5/18 *30 = 10*30=300 m
d= 18*5/18 *10 = 50 m
total distance= 650 m

total time = 60 s

AVG speed = 650 / 60 = 65/6 = 10.8 m/s

Hope it helps :)