Nora is a songwriter who collects royalties on her songs whenever they are played in a commercial or a movie. nora will earn $40 every time one of her songs is played in a commercial and she will earn $120 every time one of her songs is played in a movie. nora earned a total of $640 in royalties on 12 commercials and movies. write a system of equations that could be used to determine the number of commercials and the number of movies on which nora's songs were played. define the variables that you use to write the system.

Mrs. julien’s and mrs. castillejo’s classes are selling cookie dough for a school fundraiser. customers can buy packages of macadamia nut chip cookie dough and packages of triple chocolate cookie dough. mrs. julien’s class sold 25 packages of macadamia nut chip cookie dough and 30 packages of triple chocolate cookie dough for a total of $221.25. mrs. castillejo’s class sold 5 packages of macadamia nut chip cookie dough and 45 packages of triple chocolate cookie dough for a total of $191.25. (a) write the system of equations that model the problem. be sure to explain which equation represents which situation. (b) find the cost of each type of cookie. show your work. (c) explain which method you used to solve the system and why you chose that method.