Set up the following equations:
x represents car A's speed, and y represents car B's speed.
We'll use elimination to solve this system of equations. Multiply the first equation by 7:
Combine both equations:
Divide both sides by 28 to get x by itself:
The speed of car A is 80 mph.
Since we now know the value of one of the variables, we can plug it into the first equation:
Subtract 160 from both sides.
Divide both sides by 2 to get y by itself:
The speed of car B is 60 mph.
x represents car A's speed, and y represents car B's speed.
We'll use elimination to solve this system of equations. Multiply the first equation by 7:
Combine both equations:
Divide both sides by 28 to get x by itself:
The speed of car A is 80 mph.
Since we now know the value of one of the variables, we can plug it into the first equation:
Subtract 160 from both sides.
Divide both sides by 2 to get y by itself:
The speed of car B is 60 mph.