Multiple choice

A train with 90 kmph crosses a bridge in 36 s. Another train 100 m shorter crosses the same bridge at 45 kmph. The time taken by the second train to cross the bridge will be

  1. 60 s

  2. 64 s

  3. 68 s

  4. 72 s
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Train 1: 90 kmph = 25 m/s. Time = 36s. Distance (Bridge + Train1) = 25 * 36 = 900m. Train 2: 45 kmph = 12.5 m/s. Length = Train1 - 100. Distance (Bridge + Train2) = Bridge + Train1 - 100 = 900 - 100 = 800m. Time = 800 / 12.5 = 64s.

AI explanation

The first train travels at 90 kmph, which is 25 m/s, so the combined length of the train and the bridge is 25 multiplied by 36 equals 900 m. The second train is 100 m shorter, making its combined length 800 m, and its speed is 45 kmph, which is 12.5 m/s. Using the time formula, the required time is 800 divided by 12.5 equals 64 s.

Keep practicing — related questions