\[\frac{k - 2p}{p} = 3\]
\[\frac{k}{p} - \frac{2p}{p} = 3\]
\[\frac{k}{p} - 2 = 3\]
\[\frac{k}{p} = 3 + 2 = 5\]
\[\frac{6p - 7k}{p} = \frac{6p}{p} - \frac{7k}{p} = 6 - 7 \cdot \frac{k}{p} =\]
\[= 6 - 7 \cdot 5 = 6 - 35 = - 29.\]