Question

A train crosses a 220 m long bridge in 20 seconds. if the length of the train is 100 m, what is the speed of the train?

Answer 1

length of bridge=220m.
length of train=100m.
total=320m
speed=320/20=16
16m/s

Answer 2

The length bridge is given as 220 m.

The length of train is given as 100 m.

We are asked to calculate the speed of the train.

While crossing the bridge, the train has to cross his own length also.

Hence, the total distance [S] travelled by the train to cross the bridge is -

                                         S = 220 m+100 m

                                            = 320 m.

The time taken by the train to cross the bridge [t] = 20 seconds.

The speed of the train is calculated as-

                                                        $Speed\ V=\frac{S}{t}$

                                                                        $=\ \frac{320\ m}{20\ s}$

                                                                        $= 16\ m/s$   [ans]