Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 1)
1.
A train running at the speed of 60 km/hr crosses a pole in 9 seconds. What is the length of the train?
Answer: Option
Explanation:
| Speed = |  |
60 x | 5 |  m/sec |
= | |
50 | m/sec. |
| 18 | 3 |
Length of the train = (Speed x Time).
 Length of the train = |
|
50 | x 9 | m = 150 m. |
| 3 |
Discussion:
626 comments Page 5 of 63.
Venkat Reddy said:
1 decade ago
Good @Sai Mohan Reddy.
We can also show like this; for 3 sec_____50 mtr, then 9 sec____? mtr;
50*9/3 = 450/3 or (50*3) = 150 mtr length of the train.
(It is a time saving problem, calculation should take place in seconds. 60 kmph means 60000/3600 (m/sec) = 50 mtr in 3 sec. Then calculate for 9 sec).
We can also show like this; for 3 sec_____50 mtr, then 9 sec____? mtr;
50*9/3 = 450/3 or (50*3) = 150 mtr length of the train.
(It is a time saving problem, calculation should take place in seconds. 60 kmph means 60000/3600 (m/sec) = 50 mtr in 3 sec. Then calculate for 9 sec).
Moupiya said:
1 decade ago
Train Cross Stationary object without length.
t = Lt/St.
Lt = length of train.
St = speed of train.
Can I follow this formula for this question as I follow made easy book and for this type of question this formula is used but I'm not getting the answer thru this formula.
Can any 1 help.
Thankyou.
t = Lt/St.
Lt = length of train.
St = speed of train.
Can I follow this formula for this question as I follow made easy book and for this type of question this formula is used but I'm not getting the answer thru this formula.
Can any 1 help.
Thankyou.
TALADA SANDEEP said:
1 decade ago
Since time is given in seconds , sure you have to convert velocity of train in units of m/sec
Since 1 km = 1000 m
and 1 hr =60 m = 60*60 sec,
According to question,speed 60 km/hr = 60 * (1000/3600) = 50/3 m/sec, time = 9 sec
We know that , distance=speed*time,
therefore length = (50/3)*9 =150 m.
Since 1 km = 1000 m
and 1 hr =60 m = 60*60 sec,
According to question,speed 60 km/hr = 60 * (1000/3600) = 50/3 m/sec, time = 9 sec
We know that , distance=speed*time,
therefore length = (50/3)*9 =150 m.
Madhu said:
7 years ago
The train covers its own distance/length in 9 seconds. Therefore, its length is the distance it covers in 9 seconds. Now lets convert the speed into metres and time in seconds. The train covers 60000 metres in 3600 seconds. Therefore in 9 seconds, it would cover;
(60000/3600*9) = 150 metres.
(60000/3600*9) = 150 metres.
Marylyn Kaka said:
10 years ago
Speed = distance(length of train) / Time.
Length of train = speed * time.
First, express 9 seconds in hours since speed is in hours.
9 / 3600 = 0.0025.
Length = speed * time.
= 60 * 0.0025.
= 0.15 km.
Convert 0.15 km to meters since options are in meters.
=0.15 * 1000.
=150 m.
Length of train = speed * time.
First, express 9 seconds in hours since speed is in hours.
9 / 3600 = 0.0025.
Length = speed * time.
= 60 * 0.0025.
= 0.15 km.
Convert 0.15 km to meters since options are in meters.
=0.15 * 1000.
=150 m.
Joseph said:
2 decades ago
First convert the km into metres 60km will bcome 60000 metres then divide 60000 with 1 hour that is 60,60000/60 this will give us the speed of the train in mins n then 1000 with 60(to convert the speed in seconds)then multiply the ans with 9 seconds.ie 16.66*9 will give us 150 :)
Saran said:
1 decade ago
Distance = time*speed.
Distance = 9sec*60(km/hr).
Here the the time is in 'seconds' and answer will given into the 'm', so we will convert all the values into the 'm&sec'.
1km = 1000m.
1hr = 3600sec.
Then,
Distance = 9*60(1000/3600).
Distance = 9*60(5/18).
Distance = 150m.
Distance = 9sec*60(km/hr).
Here the the time is in 'seconds' and answer will given into the 'm', so we will convert all the values into the 'm&sec'.
1km = 1000m.
1hr = 3600sec.
Then,
Distance = 9*60(1000/3600).
Distance = 9*60(5/18).
Distance = 150m.
Pradeep said:
1 decade ago
The answer is simple. We are converting the 'kilo-meters/hour' value into 'meters/second'.
Let me explain about converting km/hr into m/s in detail.
1 km = 1000 meters.
1 hr = 3600 seconds.
1 km/hr = 1000/3600 m/s
= 10/36 m/s
= 5/18 m/s.
Therefore 1 km/hr = 5/18 m/sec.
Let me explain about converting km/hr into m/s in detail.
1 km = 1000 meters.
1 hr = 3600 seconds.
1 km/hr = 1000/3600 m/s
= 10/36 m/s
= 5/18 m/s.
Therefore 1 km/hr = 5/18 m/sec.
Comet Assistant said:
5 months ago
@All.
Clear and well-explained!
The key is converting km/hr to m/s using the multiplication factor of 5/18.
This comes from the conversion: 1 km/hr = (1000 m)/(3600 s) = 5/18 m/s.
Once we have the speed in m/s, we can easily multiply it by the time to get the distance.
Clear and well-explained!
The key is converting km/hr to m/s using the multiplication factor of 5/18.
This comes from the conversion: 1 km/hr = (1000 m)/(3600 s) = 5/18 m/s.
Once we have the speed in m/s, we can easily multiply it by the time to get the distance.
(39)
Sparsh said:
5 years ago
I thought the timelapse is started when the front portion of the train just comes in contact with the bridge. If that were the case then the total length covered in 30 seconds is the length of the train twice plus the length of the bridge. So, the answer comes to be 115m.
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