Due to lace of funding, the number of students enrolled at the city college went from 7000 last year to 4000 this year. Fine the percent decrease in enrollment

There is 42.8% of decrease in enrollment comparing to previous year.

42.8% of 7000 is 3000 which is the difference. Just divide 3000/7000 to get the numbers

In other words, new enrollmeny is 57.1% of the previous one