jmc

Since 7 knicks = 2 knacks, we get the conversion factor $\frac{7\text{ knicks}}{2\text{ knacks}}=1$. Likewise, we can get the conversion factor $\frac{3\text{ knacks}}{4\text{ knocks}}=1$. We find that 24 knocks are equal to $$24\text{ knocks}\cdot \frac{3\text{ knacks}}{4\text{ knocks}}\cdot \frac{7\text{ knicks}}{2\text{ knacks}}=\boxed{63}\text{ knicks}.$$