Speed, Time and Distance
- A car travels 80 km. in 2 hours and a train travels 180 km. in 3 hours. The ratio of the speed of the car to that of the train is :
-
View Hint View Answer Discuss in Forum
Speed = Distance Time
∴ Speed of car : Speed of train= 80 : 180 = 40 : 60 = 2 : 3 2 3 Correct Option: A
Speed = Distance Time
∴ Speed of car : Speed of train= 80 : 180 = 40 : 60 = 2 : 3 2 3
- Two trains of equal length are running on parallel lines in the same direction at 46 km/h and 36 km/h. The faster train passes, the slower train in 36 seconds. The length of each train is :
-
View Hint View Answer Discuss in Forum
Let the length of each train be x metre.
Relative speed = 46 – 36 = 10 kmph= 10 × 5 metre/second 18 = 25 metre/second 9 ∴ 2x = 36 (25/9) ⇒ 2x = 36 × 25 = 100 9
⇒ x = 50 metreCorrect Option: B
Let the length of each train be x metre.
Relative speed = 46 – 36 = 10 kmph= 10 × 5 metre/second 18 = 25 metre/second 9 ∴ 2x = 36 (25/9) ⇒ 2x = 36 × 25 = 100 9
⇒ x = 50 metre
- Two trains start from a certain place on two parallel tracks in the same direction. The speed of the trains are 45 km/hr and 40 km/hr respectively. The distance between the two trains after 45 minutes will be
-
View Hint View Answer Discuss in Forum
Relative speed = 45– 40 = 5 kmph
∴ Required distance = 5 × 45 km 60 = 15 km = 3 km 750 4 Correct Option: C
Relative speed = 45– 40 = 5 kmph
∴ Required distance = 5 × 45 km 60 = 15 km = 3 km 750 4
- A boy started from his house by bicycle at 10 a.m. at a speed of 12 km per hour. His elder brother started after 1 hr 15 mins by scooter along the same path and caught him at 1.30 p.m. The speed of the scooter will be (in km/hr)
-
View Hint View Answer Discuss in Forum
Let the speed of Scooter be x Distance covered by cycling in
3 1 hours = Distance covered by scooter in 2 2 1 hours 4 ⇒ 12 × 7 = x × 9 2 4 ⇒ x = 12 × 7 × 2 9 = 56 = 18 2 kmph 3 3 Correct Option: C
Let the speed of Scooter be x Distance covered by cycling in
3 1 hours = Distance covered by scooter in 2 2 1 hours 4 ⇒ 12 × 7 = x × 9 2 4 ⇒ x = 12 × 7 × 2 9 = 56 = 18 2 kmph 3 3
- A policeman goes after a thief who has 100 metres start, if the policeman runs a kilometre in 8 min, and the thief a km in 10 min, the distance covered by thief before he is over-powered is
-
View Hint View Answer Discuss in Forum
Relative speed = 1000 − 1000 8 10 = 5000 − 4000 = 1000 m/minute 40 40 ∴ Required time = 100 1000 40 = 4000 = 4 m/minute 1000 ∴ Distance covered by the thief = 1000 × 4 10
= 400 metresCorrect Option: B
Relative speed = 1000 − 1000 8 10 = 5000 − 4000 = 1000 m/minute 40 40 ∴ Required time = 100 1000 40 = 4000 = 4 m/minute 1000 ∴ Distance covered by the thief = 1000 × 4 10
= 400 metres