Average Speed = Total Distance / Total Time Let's assume the distance between points A and B is 'd' kilometers. The time taken to travel from A to B at a speed of 30 km/h would be: Time1 = Distance / Speed = d / 30 Similarly, the time taken to travel from B to A at a speed of 20 km/h would be: Time2 = Distance / Speed = d / 20 The total time taken for the round trip (A to B and B to A) would be the sum of Time1 and Time2: Total Time = Time1 + Time2 = d / 30 + d / 20 To find the average speed, we need to calculate the total distance traveled. Since the car is going from A to B and then back to A, the total distance is 2d. Now we can substitute the values into the average speed formula: Average Speed = Total Distance / Total Time = 2d / (d / 30 + d / 20) To simplify the expression, we can find a common denominator and add the fractions: Average Speed = 2d / (3d/60 + 2d/60) = 2d / (5d/60) = 2d * (60 / 5d) = 24 km/h Therefore, the average speed of the car for the round trip is 24 km/h.