Ninety percent of the ninth grade students at richbartville high school take algebra. if 180 ninth grade students take algebra, how many ninth grade students do not take algebra?
give answer and explain how to do it i'm so confused!

Let the total number of students be x.

Now, according to your question, 90% of x  =  180

= 90/100 * x = 180

90x = 18000

Thus, x = 18000/90

= 200.

Thus, the total number of students are 200. Out of these, 180 are taking algebra. Thus, 20 students are not taking algebra.

Ibelieve it's a. 2.2 - x = -10.85 (plz tell me if it's right : ) )