37 there are 15 plates in a kitchen cabinet. the diameter of each plate is either 7 inches or 12 inches. the diameter of all 15 plates combined is 140 inches. which system of equations can be used to find the number of 7-inch plates, x, and the number of 12-inch plates, y, that are in the cabinet? a x + y = 140 12x + 7y = 15 b 7x +12y = 140 7x + 12y = 15 cx + y = 15 7x + 12y = 140 d x + y = 15 12x + 7y = 140