A motorist travel to a place 150 km away at an average speed of 90 km/hr and returns at 30 km/hr.His average speed for the whole journey in km/hr is Choose the correct answer
A) 36km/hr
B) 37 km/hr
C) 35 km/hr
D) 45 km/hr
E) None of these
Explanation:   Average speed will be   2xy/x+y km/hr   = {2(90)(30)}/{90+30} km/hr   = 45 km/hr   Answer: Option 45 km/hr
<result>D</result>
A motorist travel to a place 150 km away at an average speed of 90 km/hr and returns at 30 km/hr.His average speed for the whole journey in km/hr is