Question

train-a crosses a stationary train-b in 50 seconds and a pole in 20 seconds with the same speed. the length of the train-a is 200 meters. what is the length of the stationary train-b ? select one: a. 260 meters b. 360 meters c. cannot be determined d. 300 meters

Answer 1

train b is 360 metres long

Answer 2

Explanation:

Step-by-step explanation:

Non of these

Step-by-step explanation:

Given:

Train A crosses a stationary Train B in 50 sec.

Train A crosses a pole in 20 sec.

Speed is same in both case.

To find:

Lenght of train B

Point To be remembered

1)Crossing a pole means travelling own lenght.

2) Speed(s)= \dfrac{Distance(x)}{Time(t)}Speed(s)=

Time(t)

Distance(x)

How to find:

First we will find the speed of train by using above formula then we will find the required length.

Solution:

t = 20 sec

x = 240 m [from 1]

s = ?

As we know,

$\begin{gathered}\begin{gathered}\sf s= \dfrac{x}{t} \\ \sf \: s = \dfrac{240}{20}\\ \sf s=12\end{gathered}\end{gathered}$

s= tx

s= 20240

s=12

s= tx

s= 20240

s=12

Now,

s = 12 m/sec

t = 50 sec

x = ?

Again,

$\begin{gathered}\sf \: x \:= s \times t \\ \sf = 12 \times 50 \\ = 600 \: m\end{gathered}$

x=s×t

=12×50

=600m

The required length of Train B is 600 m and our final answer is non of these.