SPEED, TIME AND DISTANCE (CDS)

Total Questions: 54

11. A passenger train and a goods train are running in the same direction on parallel railway tracks. If the passenger train now takes three times as long to pass the goods train, as when they are running in opposite directions, then what is the ratio of the speed of the passenger train to that of the goods train? (Assume that the trains run at uniform speeds) [2018 (I) Morning Shift]

Correct Answer: (a) 2 : 1
Solution:Let the speed of passenger train be x km/h,

12. A man can row at a speed of x km/h in still water. If in a stream which is flowing at a speed of y km/h it takes him z h to row to a place and back, then what is the distance between the two places? [2018 (I) Morning Shift]

Correct Answer: (b)
Solution:Downstream speed of man = (x + y) km/h

13. A car has an average speed of 60 km/h while going from Delhi to Agra and has an average speed of y km/h while returning to Delhi from Agra (by travelling the same distance). If the average speed of the car for the whole journey is 48 km/h, then what is the value of y? [2018 (I) Morning Shift]

Correct Answer: (c) 40 km/h
Solution:We know that, if a car travels a distance at ‘a’ km/h and returns at ‘b’ km/h, then

14. If a train crosses a km-stone in 12 s, how long will it take to cross 91 km-stones completely if its speed is 60 km/h? [2017 (II) Evening Shift ]

Correct Answer: (b) 1 h 30 min 12 s
Solution:We have, speed of train = 60 km/h

15. In a 100 m race, A runs at 6 km/h. If A gives B a start of 8m and still beats him by 9 s, what is the speed of B ? [2017 (II) Evening Shift ]

Correct Answer: (b) 4.8 km/h
Solution:Speed of A = 6 km/h

16. A boy went to his school at a speed of 12 km/h and returned to his house at a speed of 8 km/h. If he has taken 50 min for the whole journey, what was the total distance walked ? [2017 (II) Evening Shift ]

Correct Answer: (b) 8 km
Solution:Let the distance between school to house is x km.

17. A man rows down a river 18 km in 4 h with the stream and returns in 10 h. [2017 (II) Evening Shift ]

Consider the following statement
1. The speed of the man against the stream is 1.8 km/h.
2. The speed of the man in still water is 3.15 km/h.
3. The speed of the stream is 1.35 km/h.

Which of the above statements are correct?

Correct Answer: (d) 1, 2 and 3
Solution:Let the speed of man in still water = x km/h

18. A man travelled 12 km at a speed of 4 km/h and further 10 km at a speed of 5 km/h. What was his average speed ? [2017 (II) Evening Shift ]

Correct Answer: (a) 4.4 km/h
Solution:

19. In a 100 m race A runs at a speed of 5/3 m/s. If A give a start of 4 m to B and still beats him by 12 s, what is speed of B [2017 (I) Morning Shift ]

Correct Answer: (c)
Solution:Let the speed of B be x m/s.

20. A passenger train departs from Delhi at 6 pm for Mumbai. At 9 pm an express train, whose average speed exceeds that of the passenger train by 15 km/h leaves Mumbai for Delhi. Two trains meet each other mid-route. At what time do they meet, given that the distance between the cities is 1080 km? [2017 (I) Morning Shift ]

Correct Answer: (d) 6 am
Solution: