Let's begin by listing out the information given to us:
Cost (c) = 44, Markup % (m) = 80% = 0.8, selling price (p) = ?
The selling price of the shirt is given by:
[tex]\begin{gathered} \text{Markup \% }=\frac{SellingPrice-Cost}{Cost}\cdot100\text{ \%} \\ m=\frac{p-c}{c} \\ 80\text{ \%}=\frac{p-44}{44}\Rightarrow80\text{ \%}\cdot44=p-44 \\ 0.8\cdot44=p-44 \\ 35.2=p-44 \\ p=35.2+44=79.2 \\ p=79.3 \end{gathered}[/tex]