# Thread: dont know what to do with this question.

1. ## dont know what to do with this question.

A train overtakes two persons who are walking, in the same direction in which the train is going, at speed of 2 km/hr and 4 km/hr and passes them completely in 9 sec and 10 sec respectively. Find the length and speed of train.

2. I hope I am not mistaken but I believe this is unsolvable.

The answeres would vary depending on the amount of time that has taken place while the two people have been walking (or the distance between them)

I believe you need the distance between the two people to solve this.

3. Originally Posted by nanooji
A train overtakes two persons who are walking, in the same direction in which the train is going, at speed of 2 km/hr and 4 km/hr and passes them completely in 9 sec and 10 sec respectively. Find the length and speed of train.
2 km/hr = 5/9 m/s

4 km/hr = 10/9 m/s

let the train length = L meters

train speed = v m/s

rate * time = distance

(v - 5/9)9 = L

(v - 10/9)10 = L

(v - 5/9)9 = (v - 10/9)10

9v - 5 = 10v - 100/9

100/9 - 5 = v

55/9 m/s = v

22 km/hr = v

L = 50 m