Question

two trains, 100m and 80m In length are running in same direction. The first run at the rate of 51m/s and second at the rate of 42m/s. How long will they take to cross each other?

Answer 1

Answer:

They cross each other after 20 seconds.

Step-by-step explanation:

Given : Two trains, 100m and 80m In length are running in same direction. The first run at the rate of 51m/s and second at the rate of 42m/s.

To find : How long will they take to cross each other?

Solution :

The relationship between time distance and speed is

$\text{Time}=\frac{\text{Distance}}{\text{Speed}}$

First train,

Covers distance $d_1=100 m$

Speed of train x = 51 m/s

Second train,

Covers distance $d_2=80 m$

Speed of train y = 42 m/s

Total distance covered = $d_1+d_2=100+80=180 m$

Relative speed of the train = 51 - 42 = 9 m/s

(since trains are running in the same direction)

As per the formula,

$T=\frac{\text{Total distance}}{\text{Relative speed}}$

$T=\frac{180}{9}$

$T=20 s$

Therefore, They cross each other after 20 seconds.