It is given that the general equation is:
[tex]A=mp+b[/tex]Here A is the number of people attending and p is the price of ticket.
Find the values of m and b by the conditions.
When A=1850, p=17 so it follows:
[tex]1850=17m+b\ldots(i)[/tex]When A=2700, p=13 so it follows:
[tex]2700=13m+b\ldots(ii)[/tex]Subtract (ii) from (i) to get:
[tex]\begin{gathered} 1850-2700=17m-13m \\ m=\frac{1850-2700}{4}=\frac{-425}{2}=-212.5 \end{gathered}[/tex]Substitute the value of m in (i) to get:
[tex]\begin{gathered} 1850=17(-\frac{425}{2})+b \\ b=\frac{10925}{2}=5462.5 \end{gathered}[/tex]So the equation becomes:
[tex]\begin{gathered} A=\frac{-425}{2}p+\frac{10925}{2} \\ 2A=-425p+10925 \end{gathered}[/tex]Hence the linear equation is 2A=-425p+10925.