Problems on Trains

tarunceo

Par 100 posts (V.I.P)
Hi,

The most common questions in quant section are asked about Train speed, distance etc. Let's have a thread where we shall discuss problems on Trains.

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
 

tarunceo

Par 100 posts (V.I.P)
Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:

A. 50 m
B. 72 m
C. 80 m
D. 82 m
 

tarunceo

Par 100 posts (V.I.P)
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
 

tarunceo

Par 100 posts (V.I.P)
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
 
Hi,

The most common questions in quant section are asked about Train speed, distance etc. Let's have a thread where we shall discuss problems on Trains.

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 * 5/18}m/sec = {50/3}m/sec
Length of the train = (speed * Time) = {50/3 * 9}m = 150m
 
Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:

A. 50 m
B. 72 m
C. 80 m
D. 82 m

Answer: Option A

Let the length of each train be x metres.

Then, distance covered = 2x metres.

Relative speed = (46 - 36) km/hr

= (10 * 5/18)m/sec
= (25/9)m/sec
so that 2x/36 = 25/9
2x = 100
x = 50
 
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 * 5/18)m/sec = (25/2)m/sec
Time = 30 sec
Let the length of bridge be x metres.
Then, (130 + x)/30 = 25/2
= 2 (130 + x) = 750
x = 245m
 
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

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)/ x+y = 23
27x + 17y = 23x + 23y
4x = 6y
x/y = 3/2
 
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