I need help. pleaase with the whole thing ..only two questions

What is the solution to the system of the equations? x = y - 3 x + 3y = 13

James was playing a game with his friends. he won 35 points. then he lost 15, lost 40 and won 55. how did he come out

60 musicians applied for a job at a music school. 14 of the musicians play both guitar and drums, 28 play drums, 18 play the guitar. what is the probability that the applicant who gets the job plays drums or guitar?