Let's begin by identifying key information given to us:
Number of times she woke early (e) = 6
Total number of days (t) = 80 days
The percentage of days she's been getting up early is given by:
[tex]\begin{gathered} \text{\%}n\text{=}\frac{e}{t}\cdot100\text{\%} \\ \text{\%}n=\frac{6}{80}\cdot100\text{\%} \\ \text{\%}n=7.5\text{\%} \end{gathered}[/tex]Mary has gotten up early 7.5% of the days