Question

Q3. A passenger train 150m long, passes a railway platform 200m long in 35
seconds. Find the speed of the train in km/hr.
a) 56 km/hr
b) 60 km/hr
c) 42 km/h
d) 36 km/hr​

Answer 1

Given

Length of passenger train =150m

Length of railway platform = 200m

Time =35m/s

To Find

Speed of the train

$\sf\huge\bold{\underline{\underline{{Solution}}}}$

Option d) 36km/hr is correct

Here , distance formula will be used .

Distance=speed ×time

Distance will be the length of the platform + length of the train.

Total distance=length of platform+length of the train

=>Distance=200m+150m=350m

Time is 35m/s

=>Distance=speed × time

=>350=35×speed

=>350÷35=speed

speed =10m/s

Now,we find the speed in m/s we have to convert it into km/hr

For converting m/s into km/hr=>

$\sf\bold{=>\dfrac{m}{s} = \dfrac{ \frac{1}{1000} \times km}{ \dfrac{1}{3600} \times hr}}$

$\sf \bold{= > \dfrac{m}{s} = \dfrac{3600 \times km}{1000 \times h}}$

$\sf\bold{= > \dfrac{m}{s} = \dfrac{18 \times km}{5 \times hr}}$

So,we have to multiply by 18/5 when we convert m/s into km/hr.

=>10×18/5

=>2×18

=36km/hr