Question

A man standing on a platform 225 m long notices that a train travelling at a uniform speed passes him in 6 seconds and passes the platform in 21 seconds. find (i) length of the train and (ii) the speed of train. ​

Answer 1

Step-by-step explanation:

225 m long

6 seconds 21 seconds

225 plus 6 plus 21 = 252 length wise

21 seconds plus 6 seconds = 27 seconds speed wise

im not sure if this correct

Answer 2

Answer:

• Speed of Train = 15 m/s
• Length of Train = 90 metres.

Explanation:

Given:

• Length of Platform = 225 m
• Time taken by train to pass the Man = 6 s
• Time taken by Train to pass the platform = 21 s

To find:

• Length of the Train, x =?
• Speed of the train, v =?

Solution:

Since horizontal length of Man is too small in respect to the Train, therefore Distance covered by Train to pass the Man will be equal to the length of train so,

• Distance covered by Train to pass the man = Length of Train = x metres

• Given that, time taken to pass the man = 6 sec

Hence,

Speed of train will be,

→  v = x / 6   _____equation (1)

Now,

• Distance covered by Train to pass the platform = (length of train) + (length of platform) = x + 225  metres
• And given that time taken by Train to pass the platform = 21 sec

Hence,

Speed of train will be,

→ v = ( x + 225 ) / 21    

using equation (1)

→ x / 6 = ( x + 225 ) / 21

→ 21 x = 6 x + 1350

→ 21 x - 6 x = 1350

→ 15 x = 1350

→ x = 90 metres

Putting value of x in equation (1)

→ v = x / 6

→ v = 90 / 6

→ v = 15  m/s

Therefore,

• Speed of Train = 15 m/s
• Length of Train = 90 metres.