In the first hour of a two-hour trip, a car traveled 2d kilometers, and in the second hour of the trip, the car traveled one-half that distance. What is the average rate at which the car traveled during the trip, in kilometers per hour?
Choose one: A) d B) 1/3*d C) 1/2*d D) 3/4*d E) 3/2*d
Solution:   Lets look at the information given in the question...   Total time travelled = 2 hrs   Distance travelled first hour = 2d   Distance travelled second hour = d   The question is asking for the avg speed at which the car travels for 2 hrs   We know that avg speed = total distance/total time   Lets place the information given in the question to the formula above = (2d+d)/2   = 3/2*d   We find that option E is the answer as it gives the same expression as found in our calculation above. Answer option 3/2*d
<result>E</result>
In the first hour of a two-hour trip, a car traveled 2d kilometers, and in the second hour of the trip, the car traveled one-half that distance. What is the average rate at which the car traveled during the trip, in kilometers per hour?