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?
120 metres
180 metres
324 metres
150 metres
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:
619 comments Page 4 of 62.

Raj said:   7 years ago
They are given speed in terms of km/hr,

Hence we have to convert that unit into m/hr because of all the 4 options are in terms of *meter and they are asking us the length in * 9 seconds.

After we convert in terms of m/s, then just we have to multiply the value we have converted (m/s) with 9 seconds.

I hope you will understand.

Naveen said:   11 months ago
Kilometers to meters: There are 1000 meters in 1 kilometer.

Hours to seconds: There are 60 minutes in 1 hour, and 60 seconds in 1 minute, so there are 60×60=3600 seconds in 1 hour.

So, to convert a speed from km/hr to m/sec, you multiply by 3600 seconds1000 meters​.

Now, let's simplify that fraction:
36001000 ​= 3610 ​= 185​.
(10)

Nisar Ahmed said:   2 years ago
60 Km/hr.
1 km = 1000 m
1 hr = 60 min.
1 min = 60 sec.

Converting km/hr into m/sec.
1000m / 3600sec = 5/18,
So, we got this 5/18, Got it.

Now, Just multiply this by the actual value,
(Distance = Speed × Time),
that is; 60 * 5/18 = 50/3 m/sec and this distance is for one sec.

For 9 sec,
multiply 50/3 by 9.
50/3 * 9 = 150m.
(54)

Sikkanthar said:   1 decade ago
Here they are converting the unit of speed from kmph into m/s.

So they are taking the equal value of each one like.

Km = 1000m.

1 hour = 3600s.

So they are using the value of 5/18 here.

They what formula they were used to solve this problem means.

Length/time = speed.

So we can calculate unknown with help of given data.

Nagaraju said:   1 decade ago
Here we have to think that they are asking the length of train.
First we have conform that all the values given are same format or not .
if not we have to convert them into one format depending on the answers given to us.
Then it is possible to get the correct answer.

The first answer explanation by Sundar is very good .

Aathilakshmi said:   3 years ago
Length of the train = Speed × Time.

Time=9s.

Speed = 60 km/hr. (To convert speed into m/s from km/hr)
1km = 1000m so 60km = 60000m.
1 hr = 3600seconds.

Speed = 60000/3600 m/s.
= 50/3 m/s.

Length of the train = Speed × time.
= 50/3×9.
= 150m.
(78)

Muhammad Abdurrehman said:   10 years ago
Solution:

All Quantities are given in question.

Note: Answer is in the meter so will convert km/hr to m/s.

Given Data:

1. Speed = 60km/hr = 60*(1000/3600) = 100/6 m/s = 16.666m/s.

2. Time = 9 sec.

Sol: We know that speed = distance/ time.

Speed(s) = v/t or v = s * t = 16.666m/sec*9 sec.

So, s = 150 meters.

Madhira kusuma said:   3 years ago
See here :
1km=1000meters
1 hr=3600 sec.

By dividing both meters and seconds here we get =1000/3600.
At final we get 5/18.
Length = (speed×time).
L=(60×5/18).
So here we get = 50/3.
Then finally calculate the total length of the train = (50/3 × 9).
M = 150.

Thank you
(564)

Aaftab ali said:   3 years ago
Speed = 60 km/hr
Time = 9
Length = ?

Length = speed * time.

The first step convert km/hr into m/s
Formula is [ km/hr * 5/18 ] = m/s.

So,
60 km/hr * 5/18 = 50/3 m/s.

Now you have speed in metre so find the length now......
Speed * time = length.
50/3 * 9 = ? (Length).
150 = length.

So, the answer is 150 m.
(36)

Ruchita said:   9 months ago
Firstly, you need to check what's given in the question.
So, Now.
THe Time given in seconds.
Distance needed in meters.
So, convert km/hr to m/sec.
1km = 1000m
1hr = 3600sec.
1km/hr = 1000/3600 = 5/18(m/sec).
speed = (60 *5/18) = 50 /3(m/sec).
At last,
The Length = Speed * Time = (50/3 * 9) = 150meters.
(153)


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