First, we set the equations that model the situation:
Let x be the number of books sold and produced.
[tex]T_1=325+0.60x[/tex]is the cost of producing.
[tex]T_2=1.90x[/tex]is the revenue.
To break even enter, the above equations must satisfy the following condition:
[tex]325+0.60x=1.90x\text{.}[/tex]Solving the equation for x, we get:
[tex]\begin{gathered} 325=1.90x-0.60x=1.30x, \\ x=\frac{325}{1.30}=250. \end{gathered}[/tex]Answer:
[tex]250.[/tex]