so company A lost 4% today, and it had a closing price of 32.64.
let's say "x" is the opening price, namely the 100% before losing the 4%, once we lose 4% of that we end up with 100% - 4% = 96%, and low and behold, that's 32.64.
so, we know 32.64 is the 96%, and "x" is the 100%, what's "x" anyway?
![\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 32.64&96\\ x&100 \end{array}\implies \cfrac{32.64}{x}=\cfrac{96}{100}\implies \cfrac{32.64\cdot 100}{96}=x\implies 34=x](https://img.qammunity.org/2019/formulas/mathematics/middle-school/yc4jpjdkqvfwwxt9qlwyvcksl720rn5r5v.png)