A motorist travel to a place 150 km away at an avearge speed of 50 km/hr and returns ar 30 km/hr.His average speed for the whole jouney in km/hr is
36.5 km/hr
37.5 km/hr
33.5 km/hr
66.5 km/hr
Explanation:
Average speed will be
=$\dfrac{2xy}{x+y}km/hr$
=$\dfrac{2(50)(30)}{50+30}km/hr$
=37.7km/hr