Find the time taken by a 150m long train, running at a speed of 63km/h, to cross another train of length 100m, running at a speed of 45km/h in the same direction.
- A40 seconds
- B45 seconds
- C50 seconds
- D60 seconds
Solution & Step-by-step Explanation
Step 1: Calculate the total distance to be covered
When one train crosses another train, the total distance covered is the sum of the lengths of both trains.
Total Distance=150m+100m=250m
Step 2: Calculate the relative speed
Since both trains are running in the same direction, their relative speed is the difference between their speeds.
Relative Speed=63km/h−45km/h=18km/h
Convert the relative speed from km/h to m/s:
Relative Speed=18×
18
5
=5m/s
Step 3: Calculate the time taken
Time=
Relative Speed
Total Distance
=
5
250
=50seconds
When one train crosses another train, the total distance covered is the sum of the lengths of both trains.
Total Distance=150m+100m=250m
Step 2: Calculate the relative speed
Since both trains are running in the same direction, their relative speed is the difference between their speeds.
Relative Speed=63km/h−45km/h=18km/h
Convert the relative speed from km/h to m/s:
Relative Speed=18×
18
5
=5m/s
Step 3: Calculate the time taken
Time=
Relative Speed
Total Distance
=
5
250
=50seconds