Difficulty: Easy
Correct Answer: 120 m
Explanation:
Introduction / Context:
When crossing a pole, the distance covered equals the train’s length. Convert speed to m/s and multiply by time to get length directly.
Given Data / Assumptions:
Concept / Approach:
L = v * t with consistent units.
Step-by-Step Solution:
Verification / Alternative check:
At 13.333... m/s, 9 s gives exactly 120 m. Checks out.
Why Other Options Are Wrong:
150 m, 90 m, 80 m: Do not match the computed product.
Common Pitfalls:
Not converting km/h to m/s. Using 48 as m/s leads to large errors.
Final Answer:
120 m
Discussion & Comments