Question

jake has timed that a train takes 40 seconds to cross the platform he is standing on while it takes just 15seconds to cross him . if the average speed of the train is 90 kmph, what is the lenght of the platform in meters

Answer 1

Answer:

t¹= 40s

t²= 15s

speed= 90km/h= (90*1000/60*60) m/s=25m/s

speed=distance/time

distance(length of the train)=speed *time(t²)

= 25m/s*15 s= 375m

thus, now length of the train is 375 m

let x be the length of the platform

then total distance(length of the train+length of the platform)= (375+x) m

speed=d/t¹

25m/s= (375+x) m/40s

25m/s*40s=375m+xm

1000m-375m= x

625m=x

thus length of the platform is 625m

(speed is taken as uniform speed)

hope this help