Question

A train running at the speed of 90 kmph crosses a 250 m long platform in 26 seconds. What is the length of the train (in m)?

• A. 300
• B. 400
• C. 500
• D. 600

Hint:

Always ensure your units are consistent before performing calculations. If time is in seconds and distance in meters, speed must be in m/s.

Answer 1

The Correct Option is B

Step 1: Convert the train's speed to meters per second (m/s). To convert from km/h to m/s, multiply by \( \frac{5}{18} \). Speed = \( 90 \times \frac{5}{18} = 5 \times 5 = 25 \, \text{m/s} \).

Step 2: Use the formula Distance = Speed × Time to find the total distance covered. When a train crosses a platform, the total distance covered is the length of the train plus the length of the platform. Total Distance = \( 25 \, \text{m/s} \times 26 \, \text{s} = 650 \, \text{m} \).

Step 3: Calculate the length of the train. Total Distance = Length of Train + Length of Platform. \( 650 = \text{Length of Train} + 250 \). Length of Train = \( 650 - 250 = 400 \, \text{m} \).