Frank and Bob start from home in their cars and travel in opposite directions. Frank's speed is twice of Bob's. In 4 hours they are 480 kilometers apart. Find their speeds.
Let Bob's speed = B
Then Frank's speed = 2B
So Rate * Time = Total Distance.....so.......
B*4 + (2B)*(4) = 480 simplify
4B + 8B = 480
12B = 480 divide both sides by 12
B = 40 km /hr = Bob's speed
2B = 80 km/hr = Frank's speed
