Question

A train 120 meters long takes 9 seconds to cross a platform 180 meters long. What is the speed of the train in km/h?

• A. 90 km/h
• B. 100 km/h
• C. 120 km/h
• D. 80 km/h

Hint:

To convert speed from m/s to km/h, multiply by \(\frac{18}{5}\).

Answer 1

The Correct Option is C

Step 1: Calculate the total distance covered by the train while crossing the platform.
\quad Distance = Length of train + Length of platform = 120 m + 180 m = 300 m
Step 2: Time taken to cross = 9 seconds
Step 3: Calculate speed in meters per second (m/s):
\quad Speed = Distance / Time = \( \frac{300}{9} = 33.\overline{3} \, m/s \)
Step 4: Convert speed from m/s to km/h:
\quad Multiply by \( \frac{18}{5} \):
\quad Speed = \( 33.\overline{3} \times \frac{18}{5} = 33.\overline{3} \times 3.6 = 120 \) km/h
Step 5: Hence, the speed of the train is 120 km/h.