To find the percentage of students staying behind, we can use proportions.
First, let's find the number of students staying behind. Since 23 out of 30 students are going on the field trip, we subtract 23 from 30:
30 - 23 = 7 students staying behind.
Now, we can set up a proportion to find the percentage. We know that 7 students out of 30 are staying behind. Let x represent the percentage of students staying behind:
7/30 = x/100
To solve for x, we can cross-multiply:
7 * 100 = 30 * x
700 = 30x
Divide both sides by 30:
700/30 = x
x ≈ 23.3
So, approximately 23.3% of the students are staying behind.