Question

A 50m long train crosses a 150m long bridge in 12s. What is the speed of the train in km/h?

Answer 1

here u can see that the distance will be 50+ 150= 200m
so
speed =distance/time
200/12m/s
in km/h
multiply it by 18/5
200/12 × 18/5
=> 60km/h

Answer 2

Time taken to cross the bridge=Length of the train+Lenght of the bridge/Speed
                                                =(50m+150m)/12s
                                                =200m/12s
                                                =50m/3s
50m/3s in km/hr                      =50/3*18/5 km/hr
                                                =60 km/hr
Ans.=The speed of train is 60 km/hr.