Question

Two trains of 210 meters take 10 secs and 10.5 secs respectively to cross a pole. At what time will they cross each other travelling in opposite directions?

• A. 10.24 sec
• B. 13.24 sec
• C. 14 sec
• D. 16 sec

Answer 1

Answer:

A. 10.24 sec

Solution: Given: The length of the two trains is 210 meters. These take 10 secs and 10.5 secs to cross a pole. Concept used: 1. When a train crosses a pole, it covers its own length. 2. When two trains travel in opposite directions to each other, The relative speed = sum of their speed Formula used: Speed = Distance / Time Calculation: Speed of the first train = 210 / 10 ⇒ 21 m / sec Speed of the Second train = 210 / 10.5 ⇒ 20 m / sec Relative speed for opposite side = (21 + 20) m / sec ⇒ 41 m / sec Required time = Total length of trains / Relative speed ⇒ (2 × 210) / 41 ⇒ 420 / 41 ⇒ 10.24 secs They will cross each other at 10.24 secs