Question

A 100 m train is moving towards the railway station with the speed of 50 m/s. The train is 1 km away from the railway station. The time taken by the
train to cross the station is
20 s
22 s
10s
11s​

Answer 1

★ Question :

A 100 m train is moving towards the railway station with the speed of 50 m/s . The train is 1 km away from the railway station. The time taken by the  train to cross the station is

1. 20 s
3. 22 s  $\green{\star}$
5. 10s
7. 11s

★ Solution :

We have total distance , speed of the train and we need to find the time taken to cross the station . So , Isn't it easy to calculate ? We can calculate it by using speed-distance formula .

Length of the train (L) = 100 m

Speed of the train (S) = 50 m/s  $\orange{\bigstar}$

Distance b/w train and station (d) = 1 km

                                                   = 1000 m

Time taken to cross the station (t) = ? s

Total distance to be traveled (D) = Length of the train + Distance b/w train & station

➠ D = L + d

➠ D = 100 + 1000

➠ D = 1100 m  $\bigstar$

We know that ,

$:\implies \sf Speed = \dfrac{Distance}{Time}$

$:\implies \sf 50 = \dfrac{1100}{t}$

$:\implies \sf t=\dfrac{1100}{50}$

$:\implies \sf t=\dfrac{110}{5}$

$:\implies \textsf{\textbf{t\ =\ 22\ s}}\ \; \green{\bigstar}$

Time taken to cross the station is 22 s .

Option (2)

Answer 2

Given :-

• Length of train is 100 m
• Moving at speed of 50 m/s
• It is 1 km away from the railway station

To Find :-

• Time taken by the train to cross that railway station

Solution :-

❒ First , we will find out the total distance that the train will cover . The total distance covered by the train will be the sum of it's own length and the distance b/w train and the railway station .

➼ Distance b/w train and the railway station is given in km . Let's convert it into m

★ 1 km = 1000 ★

➼ Total Distance covered by the train will be :

$\sf \leadsto 1000 \; m + 100 \; m$

$\sf \leadsto 1100 \; m$

➼ As we're given the total distance covered and the speed of train , we can find out the time taken by train .

$\sf \star \; \; Time = \dfrac{Distance}{Speed}$

➼  Let's solve !

$\sf \leadsto \dfrac{1100}{50}$

$\sf \leadsto 22 \; seconds$

∴ Time taken by the train is 22 seconds

    'Option b'