A train covers 450 km at a uniform speed. If the speed had been 5 km/h more, it would have taken 1 hour less to cover the same distance. How much time will it take to cover 315 km at its usual speed?

7h

Let Initial Speed of train = a km/h

According to question ,

\(\frac{450}{a}\) - \(\frac{450}{a+ 5}\) = 1

\(\frac{450(a+5) - 450x}{a ( a+5)}\) = 1

2250 = a (a+5)

On solving ,

a = 45 km/h

Time to travel 315 km = \(\frac{315}{45}\) = 7 hours