300 mi race. If you are 20 mi closer to the finish than the start are many miles have you traveled?
The answer in the back of the book is: 160 mi. WHY?
I tried figuring out and i cant
call your distance to start line x
then your distance to finish line is 300-x
we have 300-x = x-20
that is, your (distance to finish line) equals (distance to start line) minus 20.
solve for x.