the line AC devides OB at point E which is the midpoint of line OB meaning line AC cuts OB evenly therefore line OE and EB are the same length added together they make up OB which is half the diameter of circle O because O is center point and half the diameter is the radius. If OE is 5 then EB is too and added together they make 10
This equation represent this problem because you are paid $5 an hour AFTER the first hour because you were paid an initial $20 for the first two hours.