ANSWER
![\begin{gathered} 2.90b+4.75\le39.55 \\ b\le12 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/kp1lfg69oy9pptcjsukbygzgxduc7fb73n.png)
Step-by-step explanation
Each hamburger costs $2.90 and the hamburger roll costs $4.75
Let the number of hamburgers bought be b.
This means that b hamburgers cost:
![2.90b\text{ dollars}](https://img.qammunity.org/2023/formulas/mathematics/college/leu7ox5a67s2anm9wo1barrsh8pbnab842.png)
Mario has $39.55 to spend.
Therefore, the total cost of hamburgers and the hamburger roll must be less than or equal to $39.55.
That is:
![2.90b+4.75\le39.55](https://img.qammunity.org/2023/formulas/mathematics/college/78gcr4y99nwz9vkwo7i4xqem0ijz1lb8dm.png)
Now, solve for b in the inequality:
![\begin{gathered} 2.90b\le39.55-4.75 \\ 2.90b\le34.8 \\ \Rightarrow b\le(34.8)/(2.90) \\ b\le12 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/7zbsaxrk6jaq1ul9vfs4nl8t9l83sgb77v.png)
This means that Mario can afford to buy at most 12 hamburgers.