The speed of a train is 120km/hr and the speed of another train is 140km/hr. So find the distance 1minute before they are colliding

Question

terenzreignz · Answer

Assuming they're actually going towards each other, it's the same as if one of them is stationary while the other is moving 120+140 = 260 kilometer per hour, right?

anonymous · Answer

no actually both of the trains are moving in the opposite direction and on the same track

terenzreignz · Answer

Of course they're moving in opposite directions, but if what you mean is like this...|dw:1378212194801:dw|
then of course, they'd never collide ...

terenzreignz · Answer

I'm sure this is what they mean by 'opposite directions':
|dw:1378212235987:dw|

akashdeepdeb · Answer

hehe.

anonymous · Answer

ya u got it right

terenzreignz · Answer

Well then, there's a physics thing (yes, Physics.... ) called 'relative velocity', the velocity of a body relative to another.

The relative velocity of one train with respect to the other is 260 km/hr.

Now, upon collision, their distance is 0 km.
In one minute, the distance is x.

So... Distance is equal to velocity times time.

You know the velocity (speed) you know the time (one minute) just plug in .

anonymous · Answer

Ok !
First  we think the d = 2800 km 
Now we have :|dw:1378215943814:dw|
So they come 140+120 = 260 km in 1hr