Aptitude - Problems on Trains - Discussion

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

Given that:

Speed of the Train : 60 km/h.
Crosses pole in Seconds : 9 s.

1 km = 1000 meters.
1 km/h = 60 x 1000 meters.

(i.e,) Distance = 60,000 meters.

1 hour = 60 minutes and 1 min = 60 seconds.
1 hour = 60 x 60,
(i.e,) Time = 3600 s,

Speed of the train = Distance/Time.
= 60000 m/3600 s.
= 600 m/36 s.
= 100 m/6 s.
= 50/3 meters per sec.

Length of train = Speed x Time.
= 50/3 x 9,
= 450/9.
= 150 m.

Therefore, the answer is option(D)

The train is running at 60 km per hour and it crosses the poll in 9 seconds to calculate the length of the train the formula is length = speed * time
let's calculate;

60 km = 60000 m.
60 min = 60 * 60 = 3600 sec,
let's calculate speed per second:
60000/ 3600 = 16.666666 = 16.666666 m/s.

In one second train covered the 16.666666 m.
so the train crossed the poll in 9 second.
so;
16.666666 * 9 = 150.

Given;

60 km = 60 * 1000 = 60,000m
1 Hr = 60 * 60 = 3600 Sec.
Solution:

60,000/3600 * 9 Sec. = 150m.

@All.

Here, is my expplanation.

The train runs at 60 km/hr which means it will reach 60 km in 60 mins.
therefore 1 km/min = 1000m/60s = 16.66m/1s,
The train crosses 16.66 metres for each second.
So 16.66 * 9 = 150.

@All.
Let me explain in the short.
1st look at the options is in meters so 1 kms = 1000m.
1000/60 (speed) =16.66666 per sec,
Length = speed × time.
So, the answer is 16.6666 × 9 = 150m.

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.

60km = 60000m.
1hr = 3600sec.
Now, if 60000m = 3600sec,
x = 9sec.
x = 60000m * 9sec/3600sec.
x = 150m.

if the start line and finish line are same then the time it will take to cross the line is equal to (the length of the vehicle/speed of the vehicle) that crossed the line.

The train took 9 seconds to cross the same line. It is travelling at the speed of 60 km/hr.

60 km/hr means "it took an hour to travel 60 kms."
60 km/hr = 60 km/1 hr.
= 60,000 m/60 mins.
= 60,000 m/3600 sec.
= 600 m/36 sec.
= 50 m/3 sec = 50/3 m/s.

Let length be (l)

Time taken = length/Speed.
9 sec = (l)metres/(50/3)m/s.
(l) Metres = 9 sec * (50/3) m/s.
(l) = 450/3 metres.
(l) = 150 metres.

The length of the train is 150 metres.

How 5/18 came I will explain.
1 km = 1000 m.
1hr = 60min.
1 min = 60sec.
60min = 3600 sec.
1000/3600 = 5/18.
(Cancelling two zeroes up and down and 2 * 5 = 10 and 2 * 18 = 36).