Answer:
The correct option is: 4
Step-by-step explanation:
Given system of inequalities is......
[tex]r+f\geq 16\\ \\ 4r+2f\leq 40[/tex]
Taking both inequalities as equations.....
[tex]r+f=16................(1)\\ \\ 4r+2f=40.............(2)[/tex]
Multiplying equation (1) by -2, we will get....
[tex]-2(r+f)=-2(16)\\ \\ -2r-2f=-32................(3)[/tex]
Now adding equation (2) and (3)..........
[tex]4r+2f=40\\ -2r-2f=-32\\ .............................\\ 2r\ \ \ \ \ \ \ \ \ =8\\ \\ r=\frac{8}{2}=4[/tex]
So, the maximum number of ride tickets she can buy is 4.