15. 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
A. 35 B. 37
C. 37.5 D. 40
Answer:
Average Speed = (2xy/x +y )km/hr
=(2x50 x30/ 50+30)
= 37.5 km/hr.
