A motorist travel to a place 150 km away at an average speed of 50 km/hr and returns ar 30 km/hr.His average speed for the whole journey in km/hr is:
Answer: B
Average speed will be,
\(\dfrac{2xy}{x+y} \text{ km/hr}\\
= \dfrac{2(50)(30)}{50+30} \text{ km/hr}\\
= 37.5 \text{ km/hr}\)