Answer:
875 students are enrolled in this year's freshman class after the first week of classes.
Step-by-step explanation:
Last year, there were 950 students.
This year, the class is 10% smaller. So it's number of students is 100 - 10 = 90% of last year.
0.9*950 = 855
Initially, this year class had 855 students.
During the first week, 20 enrolled.
855 + 20 = 875.
So
875 students are enrolled in this year's freshman class after the first week of classes.