\[\frac{3}{5}pk^{3} \cdot \left( 10p^{2} - 5p^{3}k - \frac{1}{3}k^{2} \right) =\]
\[= 6p^{3}k^{3} - 3p^{4}k^{4} - \frac{1}{5}pk^{5}.\]