A motorist travel to a place 150 km away at an average speed of 120 km/hr and returns at 30 km/hr.His average speed for the whole journey in km/hr is
Choose the correct answer.
A) 36 km/hr  B) 37 km/hr  C) 45 km/hr  D) 48 km/hr  E) None of these
Explanation:   Average speed will be   2xy/x+y km/hr   = {2(120)(30)}/{120+30} km/hr   = 48 km/hr   Answer: Option 48 km/hr
<result>D</result>
A motorist travel to a place 150 km away at an average speed of 120 km/hr and returns at 30 km/hr.His average speed for the whole journey in km/hr is