Official Solution:A train traveled a certain route that consisted of 3 segments. The second segment lasted twice as long as the first one and the third segment lasted twice as long as the second one. If the average speeds of the train in these segments were 60 km/h, 75 km/h, 35 km/h, what was the average speed of the train, in km/h, over the entire route? A. 40
B. 50
C. 60
D. 70
E. 80
Let's assume the time spent on the first segment was \(t\) hours, \(2t\) hours on the second, and \(4t\) hours on the third. The entire journey lasted \(t + 2t + 4t = 7t\) hours. The distances for the segments are \(60t\) km, \(75 * 2t = 150t\) km, and \(35 * 4t = 140t\) km, respectively. Thus, the average speed over the entire route would be \(\frac{\text{total distance}}{\text{total time}} = \frac{60t + 150t + 140t}{7t} = 50\) km/h.
Answer: B