Two buses leave houston at the same time and travel in opposite directions. one bus averages 55 mi/h and the other bus averages 45 mi/h. when will they be 400 miles apart?

You can set this up as an equation: . 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: . Divide 100 from both sides to get . Hope that helps.