Difficulty: Easy
Correct Answer: 11 sec.
Explanation:
Introduction / Context:
To pass a fixed point, the train covers its own length at its running speed. Convert speed to m/s and divide train length by that speed to obtain time.
Given Data / Assumptions:
Concept / Approach:
Time = distance / speed = L_train / v.
Step-by-Step Solution:
v = 36 * (1000/3600) = 10 m/s.t = 110 / 10 = 11 s.
Verification / Alternative check:
At 10 m/s, in 11 s the train covers 110 m, exactly its length, thus fully clearing the point.
Why Other Options Are Wrong:
12, 13, 15, 9 s are not equal to 110/10.
Common Pitfalls:
Adding platform/tunnel length when none exists; mis-converting km/h to m/s.
Final Answer:
11 sec.
Discussion & Comments