A train travels at a speed of 18 m/s in the first 5 minutes, covers 7.5 km in the next 10 minutes and covers 12 km in another 10 minutes. What is its average speed (in km/h, rounded off to 1 decimal place) for the entire journey?
Answer & explanation
Correct answer: option 1
Distance 1 = 18 × 5 × 60 = 5400m
= 5.4 km
Total distance = 5.4 + 7.5 + 12 = 24.9km
Total time = 5 minutes + 10 minutes + 10minutes = 25 minutes
Average speed = \(\frac{24.9 × 60 }{25}\) = 59.76 km/h
= 59.8 km/h