Question

What is the formula for an eastbound car is going 4 miles per hour faster than a westbound car. the cars are 208 miles apart 2 hours after passing each other on a highway. what is the speed, in miles per hour, of the eastbound car?

Answer 1

Draw a diagram to illustrate the problem as shown below.

Let v = speed of the westbound car, mph

Because the eastbound car travels 4 mph faster than the westbound car, its speed is (v+4) mph.

After 2 hours,
the westbound car travels 2v miles west, and the eastbound car travels 2(v+4) miles east.
Because they become separated by 208 miles, therefore
2v + 2(v+4) = 208
4v + 8 = 208
4v = 200
v = 50 mph

The westbound car travels at 50 mph.
The eastbound car travels at v+4 = 54 mph

Answer: The eastbound car travels at 54 mph.