Problems on Trains -

 General Questions

Exercise :l


1. 
A train running at the speed of 60 km/hr crosses a pole in 9 seconds. What is the length of the train?
A.120 metres
B.180 metres
C.324 metres
D.150 metres
Answer: Option D
Explanation:
Speed=60 x5m/sec=50m/sec.
183
Length of the train = (Speed x Time).
 Length of the train =50x 9m = 150 m.
3


2. 
A train 125 m long passes a man, running at 5 km/hr in the same direction in which the train is going, in 10 seconds. The speed of the train is:
A.45 km/hr
B.50 km/hr
C.54 km/hr
D.55 km/hr
Answer: Option B
Explanation:
Speed of the train relative to man =125m/sec
10
   =25m/sec.
2
   =25x18km/hr
25
   = 45 km/hr.
Let the speed of the train be x km/hr. Then, relative speed = (x - 5) km/hr.
 x - 5 = 45          x = 50 km/hr.


3. 
The length of the bridge, which a train 130 metres long and travelling at 45 km/hr can cross in 30 seconds, is:
A.200 m
B.225 m
C.245 m
D.250 m
Answer: Option C
Explanation:
Speed =45 x5m/sec=25m/sec.
182
Time = 30 sec.
Let the length of bridge be x metres.
Then,130 + x=25
302
 2(130 + x) = 750
 x = 245 m.


4. 
Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
A.1 : 3
B.3 : 2
C.3 : 4
D.None of these
Answer: Option B
Explanation:
Let the speeds of the two trains be x m/sec and y m/sec respectively.
Then, length of the first train = 27x metres,
and length of the second train = 17y metres.
27x + 17y= 23
xy
 27x + 17y = 23x + 23y
 4x = 6y
x=3.
y2


5. 
A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?
A.120 m
B.240 m
C.300 m
D.None of these
Answer: Option B
Explanation:
Speed =54 x5m/sec = 15 m/sec.
18
Length of the train = (15 x 20)m = 300 m.
Let the length of the platform be x metres.
Then,x + 300= 15
36
 x + 300 = 540
 x = 240 m.

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