Question

The two trains are moving parallel to each other from Opposite direction , the length of forth train is 40 m and it's speed is 30km/hr.2nd train is 50m in length and it's speed is 40km/hr.Both trains are 40km apart from each other.
Find the time they come face to face?​

Answer 1

Step-by-step explanation:

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We have to find the time they are face to face to each other.Therefore it is not necessary to take into concideration the distance between them.

The speeds of trains are 30km and 40km

When the objects move forward we feel that,

if we are stable the other object moves backward with same speed.

Let two trains be A and B.

Here, speed of A is 30km and of B is 40km.

Let us consider to make train one stable,

we should add it's speed to train B.

Therefore now speed of train B = 40+30=70km/hr.

The distance between last two ends of trains is

50+40=90m.

Here, speed=70km/hr=70000 m/hr,distance=90m.

But, Time=Distance/Speed

=90/70000

=9/7×1000

=1.285/1000

=0.00129(approx)hr

But, 1hr=3600 seconds.

=0.00129×3600

=0.129×36

=4.644 seconds(approx).

The trains will face each other for 4.644 seconds.