<human>:  There are 400 students. 120 students take dance as their elective. 200 students take art as their elective. The rest take music. What percentage of students take music?
<bot>: How many students are in music? ** There are 400-120-200=<<400-120-200=80>>80 students in music.
What percentage of students take music? ** Thus, students in music make up (80/400)*100=<<80/400*100=20>>20% of the students.
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