Aptitude - Problems on Trains - Discussion

Good explanation, Thanks all.

Hi Sundar,

That was a damn good explanation

How to calculate 16*5/18*9?

Let length of the train be 'x' metres...
Speed of the train = 60km/hr(given)
Time = 9seconds(given)

refer the formulas for train problems...

As the time is given in seconds and answers are given in metre(train length) we are in need to convert from km/hr to m/s
km/hr = 1000m/(60min*60sec) = 5/18 m/s

Length of the train(distance covered a post)= speed * time
= (60*(5/18))*9
= (50/3)*9
= 150 m

For the train related formulas,check the READ MORE in Left corner(Important formulas)...

I'll Give Simple Logic Answer.

i.e.,
WKT,
Speed = Distance/Time.

So,
The speed of the train is given 60km/hr.
Convert Train Speed In meters and hours into Seconds.
That is,(60*1000)/(60min*60sec).

i.e.,1 km=1000m.
1 Hour=60min.
1 min= 60sec.

We get 16.67m/s.
That is, the train traveled 16.67 meters in 1 second.
Then multiply 9 seconds with 16.67 meters.

Then length of the train traveled 150 meters in 9 seconds.

Thank you all, very nice explanations.

When we say a train passes a pole in given time then basically we consider that pole as stationary point (having 0 speed) whose length is zero means actually train crosses its own length in given time frame. If we say a running train passes another train (stationery or running) then we have to consider the total length of two trains crossing each other also we have to consider the relative speed of the trains if both trains are running in same direction then relative speed is the difference of their speed and if both are running in opposite direction then their relative speed is sum of their speed.

60km/hr convert into meters = 60*5/18 = 16.66 meter/sec.
This is for 1 second = 16.66 meter.
For 9 seconds just multiply by 9 = 16.66 * 9 = 150meter.
We already know that 1km/hr = 5/18meter/second.
1 meter/second = 18/5 km/hr.

60km is converted to 60000m and 1 hour to 3600sec, there for 60000/3600 answer to 16.66 and multiple to 9sec and answer is 149.999.

So, here, the full value as 150 metres.

Thanks everyone for the answer.