assuming the test is worth 100 points.
there were 88 questions in total, she missed 11, meaning she answered 88 - 11 = 77, assuming her grade is those 77 correct ones.
if 88 is the 100%, what is 77 off of it in percentage?
[tex]\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 88&100\\ 77&x \end{array}\implies \cfrac{88}{77}=\cfrac{100}{x}\implies \cfrac{8}{7}=\cfrac{100}{x} \\\\\\ 8x=700\implies x=\cfrac{700}{8}\implies x=87.5[/tex]
