Dr. Crispino is hanging a picture showcasing all the smiling faces of her 7th graders. She wants to center it horizontally on the wall. The picture is LaTeX: 40\frac{1}{2}40 1 2 inches long, and the wall is LaTeX: 150\frac{1}{2}150 1 2 inches long. How far from each edge of the wall should she place the picture? Explain how you got your answer.