CPM Homework Help : INT1 Problem 8-72

Two cars start together and travel in the same direction. One car goes twice as fast as the other. After five hours, they are $225$ kilometers apart. How fast is each car traveling?

Hint:

Remember $d = r t$ . Draw a picture to visualize the situation.

Step 1:

Equation for car $1$ : $d = r (5)$ where r is the rate and $5$ hours is the time.

Step 2:

Equation for car $2$ : $d = 2r (5)$ , where $2r$ is twice the rate and $5$ hours is still the time.

Step 3:

distance of car $1 +$ distance of car $2 = 225$ . Solve for $r$ .