Liberty Middle School’s enrollment increased to 660 students. This is an increase of 10% over last year’s enrollment. What was last year’s enrollment?

600

Step-by-step explanation:

Last years enrollment was 100% of the number.

This year, the enrollment went up by 10%, so now, it's 110% of last years number.

Let last year's enrollment be x.

110% of x is 660

1.1x = 660

x = 660/1.1

x = 600

600

the probability is 0