Let's begin by listing out the given information:
18 students passed
Total students = 25
Number of people who did not pass = 25 - 18 = 7
7 out of 25 students did not pass. This has its percentage as:
[tex]\begin{gathered} \frac{7}{25}\cdot100\text{\%}=28\text{\%} \\ \Rightarrow28\text{\%} \end{gathered}[/tex]Therefore, 28% of the students did not pass
