You can set this up as an equation: [tex]55x+45x=400[/tex]. The 55x is how far the first bus is will have traveled in x hours and the 45x is how far the second bus will have travelled in the same x hours. Since they are traveling in opposite directions, The distances combined should equal 400 mi. That is how I got the equation. You can simplify this equation by adding similar whatcha ma calls its to get: [tex]100x=400[/tex]. Divide 100 from both sides to get [tex]x=4[/tex]. Hope that helps.
