Question

Find the length of the platform which a train 100m long travelling at 45 km per hour crosses in 25 seconds

Answer 1

speed of train =45km/h =25/2 m/s

Length of the train =100m

Time =25sec

Distance =speed *time

=25*25/2=312.5

Length of the train =100m

length of platform =312.5-100 =212.5

Answer 2

Answer:

212.5 m

Step-by-step explanation:

Let the length of the platform be x

Length of the train = 100 m

Total distance traveled by train = Length of train + Length of platform

                                                    = 100+x

Speed of the train = 45 km/ hour

Speed of train in m/s  = $45 \times \frac{5}{18} =12.5 m/s$

Time = 25 seconds

$Time = \frac{Distance}{Speed}$

$25= \frac{100+x}{12.5}$

$25 \times 12.5= 100+x$

$312.5= 100+x$

$312.5-100=x$

$212.5=x$

Hence the length of the platform is 212.5 m