Question

Two trains,each length is 100m,are running on parallel tracks. One overtakes the other in 20s and one cross the other in 10 s . find the speed of each train

Answer 1

Explanation:

◆ Let u & v be the velocity of the two trains named A & B.

While overtaking the relative velocity of train A with respect to B = u - v.

While crossing, the relative velocity of train A with respect to B = u + v.

◆Total distance to be travelled by Train A while crossing = 100 + 100 = 200.

So,

20 = 200 ÷ u-v

=> u - v = 10....1)

Also,

10 = 200 ÷ u + v

=> u + v = 20.......2)

◆◆ On solving the equation 1 & 2, we get;◆◆

u = 15 M/S of the train A / First Train.

v= 5 M/S of the train B / Second Train.

HOPE IT HELPS

Answer 2

Let velocity of trains u and v m/s resp.

rel.velo of overtaking =u - v and

crossing = u +v, to. dist =100+100=200m ,

time = t = dist / velo = 20 =200 / u - v

= u-v=10..(1)

and 10 = 200/u+v = u+v=20..

(2) sol 1 2 u=15 m/s and v=5m/s