Question

2. A train passes by a stationary man standing on the platform in 8 seconds and passes by the platform completely in 32 seconds. If the length of the platform is 270 metres, what is the length of the train? ​

Answer 1

Let length of train be "M".

A train passes a stationary man standing on the platform in 8 seconds.

Here..

• Distance (D1) = "M" m (assume)
• Time (t1) = 8 sec

The train passes the platform in 32 seconds. If the length of the train is 270 m.

Here..

• Distance (D2) = (M + 270) m
• Time (t2) = 32 sec

As, the train covers the man's distance and of platform too. So, we add distance if both.

Now, it is also said in question that train passes through the man that is stationary and of stationary platform too. So, speed is constant (same) for both.

We know that

Speed = Distance/Time

Now,

Speed of train while passing the man = Speed of train while passing (crossing) the platform.

$\implies\:\dfrac{D1}{t1}\:=\:\dfrac{D2}{t2}$

Substitute the known values in above formula

$\implies\:\dfrac{M}{8}\:=\:\dfrac{M\:+\:270}{32}$

Cross multiply them

$\implies\:M(32)\:=\:8(M\:+\:270)$

$\implies\:32M\:=\:8M\:+\:2160$

$\implies\:32M\:-\:8M\:=\:2160$

$\implies\:24M\:=\:2160$

$\implies\:M\:=\:90$

∴ Length of train is 90 m.

Answer 2

Answer:

here your answer

Step-by-step explanation:

length of the train be x meters

distance covered by the train equal to

length of the platform+length of the

train=270+x

according to question

speed of the train passes by standing

man on the platform

is length of the train/time=x/8......(1)

and

similarly

passes by platform completely

(270+x)/32...............(2)

comparing equations (1) and (2)

x/8=(270+x)/32

32x=8(270+x)

32x=2160+8x

32x-8x=2160

24x=2160

x=2160/24

x=90.

therefore the length of the train is

90 meters.