Mrs. Lewis has placemats that are in the shape of trapezoids. She knows that the perimeter of each one is 50 inches. She also knows the length of three sides: 12 inches, 12 inches, and 15 inches. What is the length of the fourth side? Enter your answer in the box.

Acollege is selling tickets for a winter fund-raiser. one day, krissa sold 14 adult tickets and 8 student tickets for a total of $376. the next day, she sold 7 adult tickets and 11 student tickets for a total of $272. krissa wanted to find the price of one adult ticket, a, and the price of one student ticket, s. she wrote and solved the following system of equations.