In a school of 145 students, each was asked to choose one or more activities from sport, music and drama.76 students choosr sport, 64 chose music and 40 students chose drama. 12 students chose both music and sport, 7 chose both sport and drama, and 21 chose both music and drama. How many students chose all three activities?
first make a row for each subject and put how many students chose said subject. then subtract the number of students that chose both from the total amount of a subject
