Motion Problem--involving trains.?

Question

Two trains start at the same spot and travel in opposite directions. One train travels 5 km/h faster than the other train. If after 4 hours the trains are 460 km apart, how fast was each train traveling?

--I can tell that the first sentence is completely extraneous; but I'm having trouble trying to suss out the formula for this problem.

Answer 1

First of all you must calculate the length of which the two trains are travveling away from each other per hour.

Therefore;

=460/4

=115

So they move away 115km per hour.

Now you just have to subtract 5 and divide by 2 to get the first train's speed.

Therefore

115-5=110

110/2=55

The first train is 55km/h so the second train must be 60km/h.

Hope that helps!

Answer 2

let x be the speed of one train and  

(x=5)be the another train

distance=speed1 *time+speed 2*time=time(speed1+speed2)

d=4hrs[x+(x+5)] ,,where the given distance is 460

so..460=4hrs[x+(x+5)]

460/4=(2x+5)

115=2x+5

115-5=2x

110=2x

x=55km/h which is the speed of one train

(x+5)=(55+5)=60km/h  the speed of another train