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
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
Solution
✅ Correct Option: 2
Understanding what we need to find: When a train crosses a bridge, it travels a distance equal to (length of train + length of bridge).
Convert speeds from kmph to m/s since time is given in seconds:
For the first train, using Distance = Speed × Time:
Let length of first train
Then:
- Length of second train (given: 100 m shorter)
- Length of bridge (from previous step)
For second train to cross the bridge:
Notice: The terms cancel out, so we don't need to find individual lengths.
Calculate time for second train:
Therefore, the second train takes 64 seconds to cross the bridge.