Cost price of 10,000 pairs of slacks is C=$19.66 and marked price is M=$21.83.
Then, the selling price of 10,000 pairs of slacks is
[tex]\begin{gathered} S=C+M \\ =19.66+21.83 \\ =41.49 \end{gathered}[/tex]So, the selling price of 10,000 pairs of slacks is $41.49.
Therefore, the selling price of each pair of slacks is
[tex]\frac{41.49}{10,000}=0.004149[/tex]So, the selling price of each pair of slacks is $0.004149.