SPEED, TIME AND DISTANCE (CDS)

Total Questions: 54

41. Three athletes run a 4 km race. Their speeds are in the ratio 16 : 15 : 11. When the winner wins the race, then the distance between the athlete in the second position to the athlete in the third position is [2015 (II) Evening Shift ]

Correct Answer: (a) 1000 m
Solution:Ratio of speeds are 16 : 15 : 11. Let speed of winner athletic be16x km/h. Similarly, second and third position of speed of athletic is 15x and 11x, respectively.

42. In a race of 100 m, A beats B by 4 m and A beats C by 2m. By how many metres (approximately) would C beat B in another 100 m race assuming C and B run with their respective speeds as in the earlier race? [2015 (II) Evening Shift ]

Correct Answer: (b) 2.04
Solution:Speed of B in first race

43. A man rows downstream 32 km and 14 km upstream and he takes 6 h to cover each distance. What is the speed of the current? [2015 (I) Morning Shift]

Correct Answer: (c) 1.5 km/h
Solution:


44. A car travels the first one-third of a certain distance with a speed of 10 km/h, the next one-third distance with a speed of 20 km/h and the last one-third distance with a speed of 60 km/h. The average speed of the car for the whole journey is [2015 (I) Morning Shift]

Correct Answer: (a) 18 km/h
Solution:Let total distance of AB be x km.


45. Two persons A and B start simultaneously from two places c km apart and walk in the same direction. If A travels at the rate of p km/h and B travels at the rate of q km/h, then A has travelled before he overtakes B a distance of [2015 (I) Morning Shift]

 

Correct Answer: (b)
Solution:Let A and B will meet aftert h at point E.

46. In a flight of 600 km, an aircraft was slowed down due to bad weather. Its average speed for the trip was reduced by 200 km/h and the time of flight increased by 30 min. The duration of the flight is [2015 (I) Morning Shift]

Correct Answer: (a) 1 h
Solution:Let the original speed of an aircraft be x km/h and its reduced speed =(x-200) km/h.



47. With a uniform speed, a car covers a distance in 8 h. Had the speed been increased by 4 km/h, the same distance could have been covered in 7 h and 30 min. What is the distance covered? [2015 (I) Morning Shift]

Correct Answer: (b) 480 km
Solution:Let the distance between A and B be x km.


48. A runs 1⅔ times as fast as B. If A given B a start of 80 m, then how far must the winning post from the starting point be so that A and B might reach it at the same time? [2015 (I) Morning Shift]

Correct Answer: (a) 200 m
Solution:Let the speed of B be x m/s.

49. A thief is noticed by a policeman from a distance of 200 m. The thief starts running and the policeman chases him. The thief and the policeman run at the speed of 10 km/h and 11 km/h, respectively. What is the distance between them after 6 min? [2015 (I) Morning Shift]

Correct Answer: (a) 100 m
Solution:Given, speed of thief = 10 km/h

50. A train takes 10 s to cross a pole and 20 s to cross a platform of length 200 m. What is the length of the train? [2014 (II) Evening Shift ]

Correct Answer: (d) 200 m
Solution:Let length of the train be l m .