In the sixth grade math interest group activities, 60% of the students did not participate, and then 30 people participated. At this time, two-thirds of the students who participated were not. How many people were there in six years? Important process

30÷2/(2+3)-60/(60+ 100)

=30÷2/5-3/8

=30÷ 1/40

= 1200 people