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A train 108 m long moving at a speed of 50 km/hr crosses a train 112 m long coming from opposite direction in 6 seconds. The speed of the second train is:
Answer: Option (D) 82 km/hr Explanation: Let the speed of the second train be x km/hr. Relative speed = (x + 50) km/hr = (x + 50) x (5/18 )m/sec = (250 + 5x)/18 m/sec. Distance covered = (108 + 112) = 220 m. Therefore 220/((250+5x)/18) = 6 => 250 + 5x = 660 => x = 82 km/hr.
Answer: Option (D) 82 km/hr
Explanation:
Let the speed of the second train be x km/hr.
Relative speed = (x + 50) km/hr
= (x + 50) x (5/18 )m/sec
= (250 + 5x)/18 m/sec.
Distance covered = (108 + 112) = 220 m.
Therefore 220/((250+5x)/18) = 6
=> 250 + 5x = 660
=> x = 82 km/hr.
See lessTwo trains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction?
Answer: Option (B) 12 Explanation: Speed of the first train = 120/10 m/sec = 12 m/sec. Speed of the second train = 120/15 m/sec = 8 m/sec. Relative speed = (12 + 8) = 20 m/sec. Therefore Required time = (120 + 120)/20 sec = 12 sec.
Answer: Option (B) 12
Explanation:
Speed of the first train = 120/10 m/sec = 12 m/sec.
Speed of the second train = 120/15 m/sec = 8 m/sec.
Relative speed = (12 + 8) = 20 m/sec.
Therefore Required time = (120 + 120)/20 sec = 12 sec.
See lessTwo trains are running in opposite directions with the same speed. If the length of each train is 120 metres and they cross each other in 12 seconds, then the speed of each train (in km/hr) is:
Answer: Option (C) 36 Explanation: Let the speed of each train be x m/sec. Then, relative speed of the two trains = 2x m/sec. So, 2x = (120 + 120)/12 => 2x = 20 => x = 10. Therefore Speed of each train = 10 m/sec = 10 x (18/5) km/hr = 36 km/hr.
Answer: Option (C) 36
Explanation:
Let the speed of each train be x m/sec.
Then, relative speed of the two trains = 2x m/sec.
So, 2x = (120 + 120)/12
=> 2x = 20
=> x = 10.
Therefore Speed of each train = 10 m/sec = 10 x (18/5) km/hr = 36 km/hr.
See lessTwo goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.
Answer: Option (B) 24 sec Explanation: Relative speed = = (45 + 30) km/hr = 75 x 5 /18 m/sec = 125/6 m/sec. We have to find the time taken by the slower train to pass the DRIVER of the faster train and not the complete train. So, distance covered = Length of the slower train. Therefore, Distance coRead more
Answer: Option (B) 24 sec
Explanation:
Relative speed = = (45 + 30) km/hr
= 75 x 5 /18 m/sec
= 125/6 m/sec.
We have to find the time taken by the slower train to pass the DRIVER of the faster train and not the complete train.
So, distance covered = Length of the slower train.
Therefore, Distance covered = 500 m.
Therefore Required time = 500 x (6/125) = 24 sec.
See lessHow many seconds will a 500 metre long train take to cross a man walking with a speed of 3 km/hr in the direction of the moving train if the speed of the train is 63 km/hr?
Answer: Option (B) 30 Explanation: Speed of the train relative to man = (63 - 3) km/hr = 60 km/hr = 60 x (5/18) m/sec = 50/3 m/sec. Therefore Time taken to pass the man = 500 x (3/50) sec = 30 sec.
Answer: Option (B) 30
See lessExplanation:
Speed of the train relative to man = (63 – 3) km/hr
= 60 km/hr
= 60 x (5/18) m/sec
= 50/3 m/sec.
Therefore Time taken to pass the man
= 500 x (3/50) sec
= 30 sec.
A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train?
Answer: Option (D) 79.2 km/hr Explanation: Let the length of the train be x metres and its speed by y m/sec. Then, x/y = 8 => x = 8y Now, (x + 264)/20 = y => 8y + 264 = 20y => y = 22. Therefore Speed = 22 m/sec = 22 x (18/5) km/hr = 79.2 km/hr.
Answer: Option (D) 79.2 km/hr
Explanation:
Let the length of the train be x metres and its speed by y m/sec.
Then, x/y = 8 => x = 8y
Now, (x + 264)/20 = y
=> 8y + 264 = 20y
=> y = 22.
Therefore Speed = 22 m/sec = 22 x (18/5) km/hr = 79.2 km/hr.
See lessA train speeds past a pole in 15 seconds and a platform 100 m long in 25 seconds. Its length is:
Answer: Option (B) 150 m Explanation: Let the length of the train be x metres and its speed by y m/sec. Then, x/y = 15 => y = x/15 . Therefore (x + 100)/25 = x/15 => 15(x + 100) = 25x => 15x + 1500 = 25x => 1500 = 10x => x = 150 m.
Answer: Option (B) 150 m
Explanation:
Let the length of the train be x metres and its speed by y m/sec.
Then, x/y = 15 => y = x/15 .
Therefore (x + 100)/25 = x/15
=> 15(x + 100) = 25x
=> 15x + 1500 = 25x
=> 1500 = 10x
=> x = 150 m.
See less