Question

two trains A and B each of length 50 m are moving with constant speed.if one train A overtakes the other in 40 sec while cross the other in 20 sec.Find the speed of each train.

Answer 1

total distance that one train move to overtake other train will be

$L = 50 + 50 = 100 m$

now we have

$t = \frac{L}{v_1 - v_2}$

so we have

$v_1 - v_2 = \frac{100}{40}$

$v_1 - v_2 = 2.5$

now similarly if two trains cross each other then the distance it move relative to each other is

L = 50 + 50 = 100 m

again by

$t = \frac{100}{v_1 + v_2}$

$v_1 + v_2 = \frac{100}{20}$

$v_1 + v_2 = 5$

now by above two equations

$v_1 = 3.75 m/s$

$v_2 = 1.25 m/s$