\[\frac{\left( 2a^{2} \right)^{3} \cdot (3b)^{2}}{\left( 6a^{3}b \right)^{2}} = \frac{2^{3}a^{6} \cdot 3^{2}b^{2}}{2^{2} \cdot 3^{2}a^{6}b^{2}} = 2.\]