Let the number of late days be x.
In one week she makes 1500 dollars so in 4 weeks she will make 1500x4=6000 dollars
80 dollars are deducted for each late day.
She wants to make atleast 5500 dollars so the inequality is given by:
[tex]\begin{gathered} 6000-80x\ge5500 \\ 6000-5500\ge80x \\ 80x\leq500 \\ x\leq\frac{500}{80} \\ x\leq6.25 \end{gathered}[/tex]So the maximum number of late days is 6.
She can come late for 6 or fewer days to make atleast 5500 dollars.