ANSWER
![t\le9](https://img.qammunity.org/2023/formulas/mathematics/high-school/vbtptlxab2xjfwjaajzgz3aqdbho38z6yg.png)
Step-by-step explanation
Let the number of hours the room is rented be h.
The college charges a reservation fee of $45 and an additional fee of $7.80 per hour.
The expression that represents these charges is:
![45+7.80t](https://img.qammunity.org/2023/formulas/mathematics/high-school/qf5e99sqkvr6yrhrciqvk1mgh7zh1q155j.png)
The chemistry club wants to spend at most $115.20. This implies that they want to spend less than or equal to that amount.
In other words, the charges must be less than or equal to $115.20:
![45+7.80t\le115.20](https://img.qammunity.org/2023/formulas/mathematics/high-school/aysth538t4bck7ahh7teywdi4w962gm4e5.png)
Solve for t by collecting like terms:
![\begin{gathered} 7.80t\le115.20-45 \\ 7.80t\le70.2 \\ (7.80t)/(7.80)\le(70.2)/(7.80) \\ t\le9 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/owp802qu2ake35r94clw9krqoyn6k11zc1.png)
Therefore, they can rent the room for at most 9 hours.