Total cost for Aubrey's dinner = $85
The percent she tips the waitstaff = 30%
we have to determine the amount which Aubrey tip the waitstaff.
The amount she tips the waitstaff = [tex]30\%[/tex] of Dinner cost
= 30% of $85
= [tex]\frac{30}{100} \times 85[/tex]
= [tex]\frac{2550}{100}[/tex]
= $25.5
Therefore, Aubrey tips $25.5 to the waitstaff.