Question

A train covers a distance of 670 km in 6h 5min.If it covers the first 390km of the journey at 90km/h find its speed for rest of the journey

Answer 1

Total Distance = 670 km

Case 1

He covers distance=390km speed=90km/hr

Time taken=distance

speed=390 =4.34 hr= 4hr+ 0.34×60 min=4hr 20 min

But we know total time taken =6h 5min

∴ Time taken in 2nd case

Total time-Time taken in 1st case=6h 05 min - 4hr 20 min

6×60min + 05min - 4 × 60min + 20min

=360min + 05min - 240min + 20min

=365min-260min

=105 min

Converting 105 min into hour =1.75 hr

∴ Time taken in 2nd case=1.75 hr

Distance in 2 nd case=total distance-distance in 1 st case=670-390=280 kmSpeed in 2 nd case=Distance in 2 nd case

Time taken in 2nd case = 2801.75 = 160 km/hr