There are 400-120-200=<<400-120-200=80>>80 students in music.

Thus, students in music make up (80/400)*100=<<80/400*100=20>>20% of the students.

# Answer

20
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
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?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
20
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?
train