Kevin is a songwriter who collects royalties in his songs whenever they are played in a commercial or a movie. Kevin will earn $50 every time one of his songs is played in a commercial and he will earn $150 every time one of his songs is played in a movie. Kevins songs were played on 6 more commercials than movies, and his total earnings in the royalties From all commercials and movies was $900. Determine the number of commercials and the number of movies in which Kevins songs where played