Aptitude - Problems on Trains - Discussion

Time = Length of the train/Speed of the train.
Time is in seconds, do speed should be in metres/Seconds.
60 km/hr = 60 × 5/18 m/s = 50/3 m/s.
9 seconds = length/50/3.
9 × 50/3 = length.
length = 3 × 50 = 150 metre.

Where,
Speed = Distance(s)/Time(t).
To convert speed into m/s from km/hr.
Then, use the formula = Speed x Time = 100/6 * 9 = 150m.

@All.

Here, 5/18 is used to convert Km/hr to m/s.

How we get 5/18? please explain to me.

Data:
T=9,
S=?,
L=?

Time = length/seconds.
S = 60*5/18.
S = 16.6666,
T = L/S.
9 = L/16.6666,
L = 9×16.6666,
L = 149.9,
L = 150.

How did the 5/18 came? Can anyone explain it?

First convert the unit km/hr into m/s, because the length of the train is given in meters.

->so ,1km=1000m and 1 hr=1*60*60=3600 secs.

Now ,as we all know, the formula for speed in terms of distance is
speed =distance /time.
=>(60*1000/3600) m/s = distance/9 secs.
=>60*5/18 = length of train/9(time taken to cross the pole by train)
=>9*60*5/18 = length of the train.
=>length of the train =150 m.

Here we can use the formula;

The time taken by train to cross an object (i.e. man, pole, tree etc.)
T = L/S.

where T= time taken by train to cross an object.
L= Length of the train.
S= Speed of Train.

we have, S = 60 km/hr.
S = 60 * 5/18 ('*' symbol used for multiplication)
S = 16.66666 meter/second
T = 9 seconds.

Now, 9 = L/16.66666.
L = 9 * 16.
L = 149.99994~ 150 meter .
Answer = 150 meters.

(MLT) Medical Lab Technician.

1 km = 1000 m,
1 hr has 3600 sec.
So, 1 km/hr = 1000m/3600s = 5/18 m/s.