You and a friend are walking together on a sidewalk to get to a particular location. The distance from the top of the sidewalk to the turn is 10 feet more than the distance from the turn to where you are going. If you cut across the lawn the distance from the top of the sidewalk to where you want to go is 40 ft. Approximate to the nearest foot how many feet of walking distance you and your friend could save by cutting across the lawn instead of walking on the sidewalk.