The average speed of a train is 20% less on the return journey than on onward journey. The train halts for half an hour at the destination station before starting on the return journey. If the total time taken for the to and fro journey is 23 hours, covering a distance of 1000 km, the speed of the train on the return journey is:

The average speed of a train is 20% less on the return journey than on onward journey. The train halts for half an hour at the destination station before starting on the return journey. If the total time taken for the to and fro journey is 23 hours, covering a distance of 1000 km, the speed of the train on the return journey is: Correct Answer 40 km/hr

Train was halted for half an hourSo, total time taken in Journey = 23 - $$\frac{1}{2}$$ = 22.5 hoursAverage speed in Whole Journey = $$\frac{{1000}}{{22.5}}$$  = 44.5 km/hrThe average speed on return journey is 20% less than onward journey.Therefore, ratio of average speed of onward and return journey,$$\eqalign{ & = \frac{{100}}{{80}} \cr & = \frac{5}{4} \cr} $$Let average speed of onward journey = 5xAverage speed on return journey = 4xAverage speed on whole journey = $$\frac{{5x + 4x}}{2}$$44.5 = $$\frac{{5x + 4x}}{2}$$89 = 9xx = 9.88Average speed on return
= 9.88 × 4
= 39.52
= 40 km/hr (Approx.)

Related Questions

Each of the question below consists of a question and three statements number I, II and III given below it. You have to decide whether the data provided in the statement are sufficient to answer the question. If the bus is travelling from Surat to Ahmadabad and a car is travelling from Ahmadabad to Surat, then what is the distance between Surat and Ahmadabad? I. The speed of a car is 40% less than the speed of bus. Bus started at 9 am and car started at 10 am and they meet at 3 pm of the same day. II. After travelling for 1 hour, because of traffic average speed of bus is decreased by 20% and covers distance between Surat to Ahmadabad in 11 hours. Original speed of car is 20% less than original speed of bus and before crossing bus it covered 200 km if starts 1 hour later than bus. After crossing car, bus covers remaining distance in 5 hours. III. Speed of bus is 10 km/hr more than the speed of car and before crossing car ratio of distances covered bus and car in same time was 5 : 4. Time taken by car to cover the distance between Ahmadabad and Surat is 2 hours 15 minutes more than time taken by bus to cover the same distance.