math
posted by mathew .
Julia and Bianca both leave the college at the same time, but in opposite directions. If Bianca travels 9 mph faster than Julia and after 4 hours they are 140 miles apart, how fast is each traveling?

Let x = Julia's speed, then x+9 = Bianca's.
Time * Speed = Distance
4(x + x+9) = 140
Solve for x, then x+9.