An express train travelled at an average speed of 100 kmph, stopping for 3 minutes after every 75 km.A local train travelled at a speed of 50 kmph, stopping for 1 minute after every 25 km. If the trains began travelling at the same time, then how many kilometres did the local train travel in the time it took the express train to travel 600 km?

Normal time taken by express train (without stoppage) = $$\frac{600}{100}=6$$ hours

Number of time it stopped = $$\frac{600}{75}=8$$

Thus, it stopped 7 times for a total time of = $$3\times7=21$$ minutes

Now, distance travelled by local train in 6 hours and 21 minutes

= 300 km in 6 hours and 12 minutes (12 stoppages)

Thus, in the last 9 minutes, it will travel = $$\frac{50}{60}\times9=7.5$$ km

$$\therefore$$ Total distance travelled = 307.5 km

=> Ans - (A)