Question

Q58. two train a & b each 66 meters long run parallel to each other in the same direction. their speeds are 50 kmph and 30 kmph respectively. in what time a will completely pass
b.

Answer 1

Given :

Two trains A and B  runs parallel to each other in the same direction. their speeds are 50 kmph and 30 kmph respectively
Length of each train=66m

Relative speed of trains A and B  =50-30=20km/hr=20x5/18 = 50/9m /s

Distance covered By slower train A
=Length of train A +length of faster train B

Disatance=66+66=132m

Time taken by the slower train to completely pass the faster train =Distance/time=132/50/9=132x9/50=23.76sec
∴ Time taken By train A to completely pass Train B is 23.76 sec

Answer 2

From the question we know that trains are moving parallel with 50 and 30 kmph speed  and length of both of them equal to 66m.
So if we want to first calculate the relative difference of speed for both trains which will  be 50 - 30 = 20 Kmph by changing this in to m/s we will got 50/9 m/s.
 now the distance covered by the train which is slower than other = length of slower train+ length of faster train = 66+66 =132.
Time in which slower train will get pass the faster one= distance/time
                                                                                     =132/50/9=23.76 seconds.
so we know our answer now.