Two stations R and S are 400 km apart from each other. A train leaves from R to S and simultaneously another train leaves from S to R. Both trains meet after 10 hours. If the speed of the first train is 4 km/hr more than the second train, then what is the speed of the slower train?

18 km/hr

Let speed of train 1 = x km/hr

Speed of train 2 = ( x+4) km/hr

According to question ,

Relative speed = \(\frac{400}{10}\) =  40 km/hr

Now ,

x + x + 4 = 40

2x = 36 km/hr

x = 18 km/hr

& x + 4 = 22 km/hr

So , Speed of slower train = 18 km/hr