Two trains, one 154 m long and the other 158 m long, coming from opposite directions crossed each other in 10 seconds. The combined speed of the two trains every hour would then be:

Choose the correct option.

Speed is the ratio of distance travelled to time spent travelling. 

Because it has just one direction and no magnitude, speed is a scalar quantity.

Total distance to be covered = Total length of both the trains

154+158 = 312

Total time taken = 10 sec

Speed =$\frac{\mathrm{Distance}}{\mathrm{Time}}$

            $=\frac{312}{10}m/s$

            $=\frac{312}{10}\times \frac{18}{5}$

            $=112.32 km/hr$

 The combined speed of the two trains every hour would then be 112.32 km/hr.