Problems on Trains Questions Answers
-
8. Speed of a goods train is 72 km/hr. This train crosses a 250 meter platform in 26 seconds. Then find the length of goods train.
- 250 meters
- 260 meters
- 270 meters
- 280 meters
Answer And Explanation
Answer: Option C
Explanation:
First convert speed from km/hr to m/sec
So, Speed = 72*(5/18) = 20 m/sec
Time = 26 seconds
Let the length of the train be x meters.
We know, Distance = Speed*Time.
[you can remember this formula as remembering DUST = D*ST... Distance=Speed*Time]
x+250 = 20*26
=> x = 270 meters
So length of the goods train is 270 meter -
9. A 300 meter long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform.
- 310 meter
- 335 meter
- 345 meter
- 350 meter
Answer And Explanation
Answer: Option D
Explanation:
Speed = Distance/time = 300/18 = 50/3 m/sec
Let the length of the platform be x meters
then
\begin{aligned}
Distance = Speed*Time \\
x+300 = \frac{50}{3}*39 \\
=>3(x+300)= 1950 \\
=> x = 350 \text{ meters}
\end{aligned} -
10. A train speeds past a pole in 15 seconds and a platform 100 meter long in 25 seconds. What is length of the train ?
- 140 meter
- 145 meter
- 150 meter
- 155 meter
Answer And Explanation
Answer: Option C
Explanation:
Let the length of the train is x meter and Speed of the train is y meter/second
Then x/y = 15 [because distance/speed = time]
=> y = 15/x
\begin{aligned}
=> \frac{x+100}{25} = \frac{x}{15} \\
x = 150 \text{ meters}
\end{aligned}
So length of the train is 150 meters -
11. 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 ?
- 1:3
- 3:2
- 3:5
- 3:7
Answer And Explanation
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,
Length of the second train = 17y metres.
[because distance = speed*time]
\begin{aligned}
\frac{27x+17y}{x+y} = 23 \\
=> 27x + 17y = 23x + 23y \\
=> 4x = 6y \\
=> \frac{x}{y} = \frac{6}{4}
\end{aligned}
So ratio of the speeds of train is 3:2 -
12. 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 ?
- 40 meter
- 45 meter
- 50 meter
- 55 meter
Answer And Explanation
Answer: Option C
Explanation:
Let the length of each train is x meter
Distance will be x+x = 2x
Relative Speed = 46-36 = 10 km/hr
= 10*(5/18) = 25/9 m/sec
Distance = Speed*Time
\begin{aligned}
2x = \frac{25}{9}*36 \\
2x = 100 \\
=> x = 50
\end{aligned}
So length of both the trains are 50 meters -
13. 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?
- 220 meter
- 225 meter
- 230 meter
- 235 meter
Answer And Explanation
Answer: Option C
Explanation:
As trains are running in opposite directions so their relative speed will get added
So, Relative speed = 120 +80 = 200 kmph
= 200*(5/18) = 500/9 m/sec
Let the length of other train is x meter then
\begin{aligned}
\frac{x+270}{9} = \frac{500}{9} \\
=> x+270 = 500\\
=> x = 230
\end{aligned}
So the length of the train is 230 meters -
14. Two 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 which they take to cross each other, is
- 9.8 seconds
- 10.8 seconds
- 11.8 seconds
- 12.8 seconds
Answer And Explanation
Answer: Option B
Explanation:
Relative Speed = 60+40 = 100 kmph
= 100*(5/18) = 250/9 m/sec
Distance = 140+160 = 300 meters
Time = Distance/Speed
\begin{aligned}
300*\frac{9}{250} = \frac{54}{5} \\
= 10.8 \text{ seconds}
\end{aligned}
So the time trains will take to cross each other will be 10.8 seconds