Two buses leave Houston at the same time and travel in oppos

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?

Solution

1. We know that one of the buses is traveling at 55 miles per hour and the other is traveling at 45 miles an hour.
2. We want to know how many hours it would take them to be 400 miles apart.
3. We use X to represent the number of hours each bus has been traveling.
4. 55x + 45x= 400
5. 100x=400 (every hour the buses are moving, they move 100 miles apart)
6. x=4
The buses will be 400 miles apart in four hours.