A train travels the first 200 km of a journey at a speed of 100 km/h and the remaining 150 km at a speed of 75 km/h. What is the average speed (in km/h) of the train for the entire journey?

Correct option is B

Given:
First distance = 200 km
Speed for the first distance = 100 km/h
Second distance = 150 km
Speed for the second distance = 75 km/h
Formula Used:
Average speed = Total distance ÷ Total time
Time = Distance ÷ Speed
Solution:
Total distance = 200 + 150 = 350 km
Time for first distance = 200 ÷ 100 = 2 hours
Time for second distance = 150 ÷ 75 = 2 hours
Total time = 2 + 2 = 4 hours
 Average speed = 350 ÷ 4 = 87.5 km/h
∴ The correct answer is 87.5 km/h.