Time, speed and distance
Top questions
See all →- A car covers 360 km in 6 hours. By how much must its speed be increased to cover the same distance in 4 hours? Answer: C. 30 km/h Answer: (C) 30 km/h Present speed = 360/6 = 60 km/h. Required speed = 360/4 = 90 km/h. Increase = 30 km/h. 1
- A train 180 m long crosses a pole in 9 seconds. How long will it take to cross a platform 270 m long? Answer: B. 22.5 seconds Answer: (B) 22.5 seconds Speed = 180/9 = 20 m/s. To cross the platform it covers 180 + 270 = 450 m: 450/20 = 22.5 s. 1
- Two trains 150 m and 210 m long are running in opposite directions on parallel tracks at 45 km/h and 63 km/h. In how much time will they completely cross each other? Answer: C. 12 seconds Answer: (C) 12 seconds Relative speed (opposite directions) = 45 + 63 = 108 km/h = 108 × 5/18 = 30 m/s. Distance = 150... 1
- Two trains, 150 m and 210 m long, run on parallel tracks in opposite directions at 45 km/h and 63 km/h. How many seconds do they take to cross each other completely? Answer: A. 12 Answer: (A) 12 Relative speed = 108 km/h = 30 m/s. Distance = 150 + 210 = 360 m. Time = 360 ÷ 30 = 12 s. 1
- Walking at 5 km/h, a man reaches his office 10 minutes late. Walking at 6 km/h, he reaches 5 minutes early. What is the distance to his office (in km)? Answer: B. 7.5 Answer: (B) 7.5 The time difference is 15 min = 1/4 h. d/5 - d/6 = d/30 = 1/4 , so d = 7.5 km. 1
- A 240 m long train crosses a pole in 12 seconds. How long (in seconds) will it take to cross a 360 m long platform? Answer: D. 30 Answer: (D) 30 Speed = 240 ÷ 12 = 20 m/s. Distance to cover = 240 + 360 = 600 m. Time = 600 ÷ 20 = 30 s. 1