Let's use the variable x to represent the inicial amount of money Julia had.
She spent 4, then 17, then 33, and the left over is 36, so we can write the following equation:
[tex]x-4-17-33=36[/tex]Solving this equation for x, we have that:
[tex]\begin{gathered} x=36+4+17+33 \\ x=90 \end{gathered}[/tex]So Julia started with $90.