Christina is using her computer to design invitations to her birthday party. the text of the invitation is contained in a rectangle with a length of 7.5 inches and a width of 5 inches. around the perimeter of the text, christina wants to have a red border of width r. around the red border, she wants a purple border of width p. find an expression for the perimeter of the completed invitation. 25 + 8r + 8p 37.5 + 6r + 2p 15 + 8r + 8p 12.5 + 4r + 4p