Farmer Joe has a barn that is 20 ft by 10 ft to shelter his cow, Bessie. The barn is completely surrounded by grass where Bessie grazes, but the inside of the barn contains no food. He tethers Bessie to one corner of the outside of the barn using a 50 ft rope. Now, Bessie will go far and wide for food. What is the total area Bessie is capable of grazing?