The percent Heidi has correct can be obtained by the rule of three.
[tex]\begin{gathered} 40\rightarrow100 \\ 36\rightarrow x \end{gathered}[/tex]Then:
[tex]x=\frac{36\cdot100}{40}=\frac{3600}{40}=90[/tex]Therefore, Heidi anwered 90% of the questions correctly.
