Final answer:
To find the total number of students at Xavier's School, we can set up a proportion using the given information. There are 12 seventh graders, which represents 30% of the total student population. Solving the proportion reveals that there are 40 total students at the school.
Step-by-step explanation:
To find the number of total students at Xavier's School, we can set up a proportion using the given information. Let x represent the total number of students at the school. We know that 30% of the students are in seventh grade, so we can set up the proportion:
12/ x = 30/100
To solve for x, we can cross-multiply and then divide:
12 * 100 = 30 * x
1200 = 30x
x = 1200/30
x = 40
Therefore, there are 40 total students at Xavier's School.