The speed of a car is 90 km in the first hour and 30 km in the second hour. What is the average speed of the car?
Pick one:
A) 50 kmph
B) 60 kmph
C) 75 kmph
D) 85 kmph
E) 90 kmph

Rationale: "explanation : s = ( 90 + 30 ) / 2 = 60 kmph b )"
Answer: B