\[\boxed{\mathbf{156}.}\]
\[1)\ a\ :b = 3 \cdot 5 \cdot 7 \cdot 11 =\]
\[= 3 \cdot 35 \cdot 11 = 3 \cdot 385 = 1155;\]
\[2)\ a\ :b = 2 \cdot 5 \cdot 23 = 10 \cdot 23 =\]
\[= 230.\]