Question

nishu is standing on railway bridge which is 180 m.he finds that a train crosses the bridge in 20 sec.but himself in 8 sec.find speed of train​

Answer 1

Step-by-step explanation:

Hope this answer is correct!

Answer 2

$\large\underline{\underline{\sf Given:}}$

• Lenght of railway bridge =180m

• Nishu crosses bridge in = 8s

• Train crosses bridge in = 20s

$\large\underline{\underline{\sf To\:Find:}}$

• Speed of train (S) = ?

$\large\underline{\underline{\sf Solution:}}$

Let,

Lenght of train = L

Speed of train = S

•°• Speed = Total Distance / Time

$\large\implies{\sf S=\frac{180+L}{20}→(1) }$

Assume S is constant and train takes 8s to pass a single point (nishu) then ,

$\large\implies{\sf S= \frac{L}{8}→(2) }$

Now ,

$\large\implies{\sf \frac{180-L}{20}=\frac{L}{8} }$

$\large\implies{\sf 8(180-L)=20L }$

$\large\implies{\sf 1440+8L=20L }$

$\large\implies{\sf L=120m}$

•°• Lenght of train is 120m

On putting value of Lenght of train in Equation 2 we get :-

$\large\implies{\sf S=\frac{120}{8}}$

$\large\implies{\sf S=15m/s }$

Convert it into km/h

$\large\implies{\sf 15×\frac{18}{5}}$

$\large\implies{\sf 54km/h}$

$\Large\underline{\underline{\sf Answer:}}$

•°• Speed of train is 15m/s or 54km/h