pre calculus
posted by sharon .
If you are driving down a 10% grade, you will always be 10% below where you would have been if you could have driven on flat ground from where you started. Suppose you descend to where you are 20 feet below your starting point. What concept does the “grade” relate to, and how far would you have been from where you started if you had driven on flat ground?
I have know clue how to solve this. please help!

since the "depth" is 10% of the horizontal distance, you'd have to drive 200' horizontally to be directly over the point 20' below.
the grade is the tangent of the angle of descent, or the slope of the road.