An eastbound car is going 4 miles per hour faster than the westbound car. The cars are 208 miles apart 2 hours after passing each other on the highway. What is the speed, in miles per hour, of the westbound car?
Let the speed of the westbound car be x mph. Then the speed of the eastbound car is (x + 4) mph. In 2 hours after the cars passed each other on the highway they both traveled 2x and 2(x+4) miles, respectively. On the other hand, 2x + 2(x+4) = 208. Solve the equation: 2x + 2x + 8 = 208; 4x = 200; x = 50.