SOLUTION
The cost per student =$5
Then let the total cost be C(n) and n be the number of students
Then required function is
![C(n)=5n+30](https://img.qammunity.org/2023/formulas/mathematics/college/izsxnywgu4ji82csvhehsww4l1hjpojcer.png)
if the total number of student is 20, n=20
The total cost is
![\begin{gathered} C(n)=5n+30 \\ C(n)=5(20)+30=100+30=130 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/jakfyxfaf0jk66mq2w3of7bvx9fqtyhtbf.png)
Then the total cost is $130
If the total number of student is 25, then n=25
The total cost becomes
![\begin{gathered} C(n)=5n+30 \\ C(n)=5(25)+30=125+30=155 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/hcfv0ju7an2dfjqt2cb33nobxxs49f41zj.png)