21) 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,
- 1) 9.8 seconds
- 2) 10.8 seconds
- 3) 11.8 seconds
- 4) 12.8 seconds
View Answer
View Explanation
Ans. 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
22) A train is 100 meter long and is running at the speed of 30 km per hour. Find the time it will take to pass a man standing at a crossin
- 1) 10 seconds
- 2) 12 seconds
- 3) 14 seconds
- 4) 16 seconds
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View Explanation
Ans. B
Explanation :
As we need to get answer in seconds, so never forget to convert speed into meter per second.
Speed = 30 km/hr = 30* 5/18 m/sec
= 25/3 m/sec
Distance = length of train = 100 meter
Required time =
\begin{aligned}
\frac{Distance}{Speed} \= \frac{100}{\frac{25}{3}} \= 100* \frac{3}{25} = 12 sec \\end{aligned}
23) How long does a train 110 meters long running at the speed of 72 km/hour take to cross a bridge 132 meters in length
- 1) 15 seconds
- 2) 12.1 seconds
- 3) 10 seconds
- 4) 8.1 seconds
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View Explanation
Ans. B
Explanation :
Speed = 72 km/hour = 72*(5/18) m/sec
= 20 m/sec
Total distance to be covered = 110+132 = 142 meters
Time = Distance/Speed
= 242/20 = 12.1 seconds
24) A train is moving at a speed of 132 km/hour. If the length of the train is 110 meters, how long will it take to cross a railway platform 165 meters lon
- 1) 7 second
- 2) 7.5 second
- 3) 8 second
- 4) 8.5 second
View Answer
View Explanation
Ans. B
Explanation :
As we need to calculate answer in seconds, so first convert speed into meter/sec.
we know 1 km/hr = 1*(5/18) m/sec
So, Speed = 132* (5/18) = 110/3 m/sec
Distance need to be covered in passing the platform =
Length of train + length of platform = 110 + 165
= 275 meters
Time = Distance/Speed
\begin{aligned}
=> Time = 275* \frac{3}{110} = \frac{15}{2} \= 7.5 seconds
\end{aligned}
25) A train is 360 meter long is running at a speed of 45 km/hour. In what time will it pass a bridge of 140 meter lengt
- 1) 20 seconds
- 2) 30 seconds
- 3) 40 seconds
- 4) 50 seconds
View Answer
View Explanation
Ans. C
Explanation :
Speed = 45 Km/hr = 45*(5/18) m/sec
= 25/2 m/sec
Total distance = 360+140 = 500 meter
Time = Distance/speed
\begin{aligned}
= 500*\frac{2}{25} = 40 seconds
\end{aligned}
26) In what time will a train 100 meters long cross an electric pole, if its speed is 144 km/
- 1) 5 seconds
- 2) 4.5 seconds
- 3) 3 seconds
- 4) 2.5 seconds
View Answer
View Explanation
Ans. D
Explanation :
First convert speed into m/sec
Speed = 144*(5/18) = 40 m/sec
Time = Distance/speed
= 100/40 = 2.5 seconds
27) A train running at the speed of 60 km/hr crosses a pole in 9 seconds. Find the length of the trai
- 1) 150 meter
- 2) 145 meter
- 3) 140 meter
- 4) 135 meter
View Answer
View Explanation
Ans. A
Explanation :
Speed = 60*(5/18) m/sec = 50/3 m/sec
Length of Train(Distance) = Speed * Time
\begin{aligned}
= \frac{50}{3}*9 = 150 meter
\end{aligned}
28) Length of train is 130 meters and speed of train is 45 km/hour. This train can pass a bridge in 30 seconds, then find the length of the bridg
- 1) 230 meters
- 2) 235 meters
- 3) 240 meters
- 4) 245 meters
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View Explanation
Ans. D
Explanation :
Let the length of bridge is X [as always we do :)]
Speed of train is = 45*(5/18) m/sec = 25/2 m/sec
Time = 30 seconds
Total distance = 130+x
We know Speed = distance/time
so,
\begin{aligned}
\frac{130+x}{30} = \frac{25}{2} \=> 2(130+x) = 750 \x = 245 \text{ meters}
\end{aligned}
So length of the bridge is 245 meters
29) Two trains 140 metre and 160 metre long run at the speed of 60 km/hr and 40 km/hr respectively in opposite direction on parallel tracks. What time these will take to cross each other
- 1) 10.7 Seconds
- 2) 10.8 Seconds
- 3) 10.9 Seconds
- 4) 11.8 Seconds
View Answer
View Explanation
Ans. B
Explanation :
Relative Speed = 60+40 = 100 Kmph
= 100*(5/18) = 250/9 m/sec
Distance to be covered = 140 + 160 = 300 metres
Time = Distance/Speed
\begin{aligned}
Time = 300*\frac{9}{250} \= \frac{54}{5} = 10.8\text{ seconds}
\end{aligned}
30) Two trains are running in opposite directions in the same speed. The length of each train is 120 meter. If they cross each other in 12 seconds, the speed of each train (in km/hr)
- 1) 30 Km/hr
- 2) 36 Km/hr
- 3) 80 Km/hr
- 4) 90 Km/hr
View Answer
View Explanation
Ans. B
Explanation :
Distance covered = 120+120 = 240 m
Time = 12 s
Let the speed of each train = x.
Then relative velocity = x+x = 2x
2x = distance/time = 240/12 = 20 m/s
Speed of each train = x = 20/2 = 10 m/s
= 10*18/5 km/hr = 36 km/hr