A goods train 350 m long passes through a tunnel of 1250 m in 80 seconds. What is the speed of the train?
- A64 km/h
- B78 km/h
- C56 km/h
- D72 km/h
Solution & Step-by-step Explanation
To cross the tunnel completely, the train must cover a total distance equal to the length of the train plus the length of the tunnel.
Total Distance=Length of train+Length of tunnel
Total Distance=350 m+1250 m=1600 m
The time taken to cover this distance is 80 seconds.
Speed=
Time Taken
Total Distance
Speed=
80
1600
=20 m/s
To convert the speed from m/s to km/h, we multiply by
5
18
:
Speed in km/h=20×
5
18
=4×18=72 km/h
Total Distance=Length of train+Length of tunnel
Total Distance=350 m+1250 m=1600 m
The time taken to cover this distance is 80 seconds.
Speed=
Time Taken
Total Distance
Speed=
80
1600
=20 m/s
To convert the speed from m/s to km/h, we multiply by
5
18
:
Speed in km/h=20×
5
18
=4×18=72 km/h