Mrs. Roth is researching what it would cost to order flower arrangements for a fancy party. She wants one large centerpiece for the head table, and smaller arrangements for the smaller tables. Springdale Florist charges $13 for each smaller arrangement, plus $51 for the large centerpiece. Emily's Flowers, in contrast, charges $50 for the large centerpiece and $14 per arrangement for the rest. If Mrs. Roth orders a certain number of small arrangements, the cost will be the same at either flower shop. What would the total cost be? How many small arrangements would that be?