00:01
In this problem, a passenger train and freight train are starting towards each other.
00:04
They start at the same time from two points that are 300 miles apart.
00:16
It says that the rate of the passenger train exceeds the rate of the freight train by 15 miles per hour, and they meet after four hours, what must the rate of each be? so the passenger train starts here and is going this direction.
00:31
Freight train starts here and is going this direction.
00:35
So here are some things that we know.
00:38
The distance of the passenger train plus the distance of the freight train must equal 300 miles total.
00:48
Now keep in mind, distance is equal to rate times time.
00:52
They both traveled for four hours because that's when they meet.
00:56
So the rate of the passenger train times four plus the rate of the freight train times four has to equal 300.
01:12
Now we could go ahead and divide everything by four.
01:18
Just since there's a four in both terms on the left, so if i divide everything by four, that gives me that the rate of the passenger train plus the rate of the freight train has to equal 300 divided by 4, which is 75.
01:33
And this would be miles per hour now...