The speed of a car is 140 km in the first hour and 40 km in the second hour. What is the average speed of the car?  Choose the correct choice from the following answers.
A) 72 kmph  B) 75 kmph  C) 30 kmph  D) 90 kmph  E) 82 kmph

Rationale: "s = ( 140 + 40 ) / 2 = 90 kmph answer : d"
Answer: D