Aptitude - Problems on Trains - Discussion

Hi.

How is possible to come 55/3?

Please advice me.

Guys why don't you'll go through the formulas given at the beginning of all the topic as this will clear most of the questions asked here at the beginning itself.

Because train are moving across the man.

The man is not considered as pole so only train distance is total distance.

Moving in the same direction that's why 60 + 6 = 66
Speed = 66 * 5/18 = 55/3.
Time = 110/(55/3).
= 110 * 3/55.
= 6 sec.

The speed can be added only if the two objects moving in opposite directions and if same direction then it should be subtracted.

Hi all.

Here we have considered the distance taken by train coming in opposite direction in almost all the problems. So here why we have not considered the distance taken by man.

Case 1: When they are in opposite direction.

Length of train in m = (Speed of train + Speed of man) in m/sec*time in sec.

Case 2: When they are in same direction.

Length of train in m = (Speed of train - Speed of man) in m/sec*time in sec.

110 m = (60 kmph + 6 kmph) * time (sec).

110 m = 66 kmph * time (sec).

110 m = 66*5/18 (m/sec) * time (sec).

Time (sec) = 110/18.333.

Time (sec) = 6 sec.

Hint: To convert km/hr = m/sec multiply by 5/18.

To convert m/sec = km/hr multiply by 18/5.

Both the man and train moving in opposite to each other so while the train crosses man, man will also move some distance so total distance travel by train will be different not only its own length.

Hence the answer is 6.6 sec.

As of the direction the relative speed would be 60+6=66. Convert it to m/sec as required to the answer. You will get 55/3 mtr/sec.

So, 55/3 = 110/t. T = 6 sec and done.

Please any one give the reason for not considering distance covered by man.