1. a train overtakes two persons who are walking in the same direction in which the train is going at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. the length of the train is: a. 45 m b. 50 m c. 54 m d. 72
Answers
Answered by
1
Let the length of the train be x km and its speed y km/hr. Then, speed relative to first man = (y-2) km/hr.
Speed relative to second man = (y-4) km/hr.
time =
x/y−2=9/60×60 and x/y−4=10/60×60
9y - 18=3600x or 10y - 40=3600x
So, 9y-18=10y-40 or y =22
x/22−2=9/3600 or x = 20×9/3600=1/20
= (1/20×1000)m = 50 m
Speed relative to second man = (y-4) km/hr.
time =
x/y−2=9/60×60 and x/y−4=10/60×60
9y - 18=3600x or 10y - 40=3600x
So, 9y-18=10y-40 or y =22
x/22−2=9/3600 or x = 20×9/3600=1/20
= (1/20×1000)m = 50 m
Similar questions