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A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?
Answer: Option (B) 350 m Explanation: Speed = ( 300/18) m/sec = (50/3) m/sec. Let the length of the platform be x metres. Then, ( x + 300)/39 = 50/3 => 3(x + 300) = 1950 => x = 350 m.
Answer: Option (B) 350 m
Explanation:
Speed = ( 300/18) m/sec = (50/3) m/sec.
Let the length of the platform be x metres.
Then, ( x + 300)/39 = 50/3
=> 3(x + 300) = 1950
=> x = 350 m.
See lessA train 800 metres long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 minute, then the length of the tunnel (in meters) is:
Answer: Option (C) 500 Explanation: Speed = 78 x (5/18) m/sec = 65/3 m/sec. Time = 1 minute = 60 seconds. Let the length of the tunnel be x metres. Then, ( 800 + x)/60 = 65/3 => 3(800 + x) = 3900 => x = 500.
Answer: Option (C) 500
Explanation:
Speed = 78 x (5/18) m/sec = 65/3 m/sec.
Time = 1 minute = 60 seconds.
Let the length of the tunnel be x metres.
Then, ( 800 + x)/60 = 65/3
=> 3(800 + x) = 3900
=> x = 500.
See lessA train travelling at a speed of 75 mph enters a tunnel 31/2 miles long. The train is 1/4 mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges?
Answer: Option (B) 3 min Explanation: Total distance covered = ( 7/2) + (1/4) ( miles = 15/4 miles. Therefore Time taken = 15/(4x75) ( hrs = 1/20 hrs = ( 1/20) x 60 ( min. = 3 min.
Answer: Option (B) 3 min
Explanation:
Total distance covered
= ( 7/2) + (1/4) ( miles
= 15/4 miles.
Therefore Time taken
See less= 15/(4×75) ( hrs
= 1/20 hrs
= ( 1/20) x 60 ( min.
= 3 min.
A train 110 metres long is running with a speed of 60 kmph. In what time will it pass a man who is running at 6 kmph in the direction opposite to that in which the train is going?
Answer: Option (B) 6 sec Explanation: Speed of train relative to man = (60 + 6) km/hr = 66 km/hr. = 66 x (5/18) m/sec = 55/3 m/sec. Time taken to pass the man = 110 x (3/55) sec = 6 sec.
Answer: Option (B) 6 sec
Explanation:
Speed of train relative to man = (60 + 6) km/hr = 66 km/hr.
= 66 x (5/18) m/sec
= 55/3 m/sec.
Time taken to pass the man = 110 x (3/55) sec = 6 sec.
See lessTwo trains 140 m and 160 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is:
Answer: Option (D) 8 Explanation: Relative speed = (60 + 40) km/hr = 100 x (5/18 )m/sec = 250/9 m/sec. Distance covered in crossing each other = (140 + 160) m = 300 m. Required time = 300 x (9/250) sec = 54/5 sec = 10.8 sec.
Answer: Option (D) 8
Explanation:
Relative speed = (60 + 40) km/hr = 100 x (5/18 )m/sec = 250/9 m/sec.
Distance covered in crossing each other = (140 + 160) m = 300 m.
Required time = 300 x (9/250) sec = 54/5 sec = 10.8 sec.
See lessTwo trains, each 100 m long, moving in opposite directions, cross each other in 8 seconds. If one is moving twice as fast the other, then the speed of the faster train is:
Answer: Option (C) 60 km/hr Explanation: Let the speed of the slower train be x m/sec. Then, speed of the faster train = 2x m/sec. Relative speed = (x + 2x) m/sec = 3x m/sec. (100 + 100)/8 = 3x 24x = 200 x = 25/3 . So, speed of the faster train = 50/3 m/sec = (50/3) x (18/5) km/hr = 60 km/hr.
Answer: Option (C) 60 km/hr
Explanation:
Let the speed of the slower train be x m/sec.
Then, speed of the faster train = 2x m/sec.
Relative speed = (x + 2x) m/sec = 3x m/sec.
(100 + 100)/8 = 3x
24x = 200
x = 25/3 .
So, speed of the faster train = 50/3 m/sec
= (50/3) x (18/5) km/hr
= 60 km/hr.
See lessA goods train runs at the speed of 72 kmph and crosses a 250 m long platform in 26 seconds. What is the length of the goods train?
Answer: Option (D) 270 m Explanation: Speed = 72 x (5/18) m/sec = 20 m/sec. Time = 26 sec. Let the length of the train be x metres. Then, (x + 250)/26 = 20 x + 250 = 520 x = 270.
Answer: Option (D) 270 m
Explanation:
Speed = 72 x (5/18) m/sec = 20 m/sec.
Time = 26 sec.
Let the length of the train be x metres.
Then, (x + 250)/26 = 20
x + 250 = 520
x = 270.
A 270 metres long train running at the speed of 120 kmph crosses another train running in opposite direction at the speed of 80 kmph in 9 seconds. What is the length of the other train?
Answer: Option (A) 230 m Explanation:Relative speed = (120 + 80) km/hr = 200 x (5 /18)m/sec = 500/9 m/sec. Let the length of the other train be x metres. Then, (x + 270)/9 = 500/9 x + 270 = 500 x = 230.
= 200 x (5 /18)m/sec
= 500/9 m/sec.
Let the length of the other train be x metres.
Then, (x + 270)/9 = 500/9
x + 270 = 500
x = 230.
A jogger running at 9 kmph alongside a railway track in 240 metres ahead of the engine of a 120 metres long train running at 45 kmph in the same direction. In how much time will the train pass the jogger?
Answer: Option (C) 36 sec Explanation: Speed of train relative to jogger = (45 - 9) km/hr = 36 km/hr. = 36 x (5 /18)m/sec = 10 m/sec. Distance to be covered = (240 + 120) m = 360 m. Time taken = 360/10 sec = 36 sec.
Answer: Option (C) 36 sec
Explanation:
Speed of train relative to jogger = (45 – 9) km/hr = 36 km/hr.
= 36 x (5 /18)m/sec
= 10 m/sec.
Distance to be covered = (240 + 120) m = 360 m.
Time taken = 360/10 sec = 36 sec.
See lessA train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
Answer: Option (A) 40 sec Explanation: Formula for converting from km/hr to m/s: X km/hr = X x (5/18) m/s. Therefore, Speed = 45 x (5/18) m/sec = 25/2 m/sec. Total distance to be covered = (360 + 140) m = 500 m. Formula for finding Time = Distance/Speed Required time = (500 x 2)/25 sec = 40 sec.
Answer: Option (A) 40 sec
Explanation:
Formula for converting from km/hr to m/s: X km/hr = X x (5/18) m/s.
Therefore, Speed = 45 x (5/18) m/sec = 25/2 m/sec.
Total distance to be covered = (360 + 140) m = 500 m.
Formula for finding Time = Distance/Speed
Required time = (500 x 2)/25 sec = 40 sec.
See less