If 5.5 of a = 0.65 of b, then a : b is equal to = ?

$$\eqalign{ & 5.5{\text{a}} = 0.65{\text{b}} \cr & \Rightarrow \frac{{55}}{{10}}{\text{a}} = \frac{{65}}{{100}}{\text{b}} \cr & \Rightarrow 55{\text{a}} = \frac{{65}}{{10}}{\text{b}} \cr & \Rightarrow 550{\text{a}} = 65{\text{b}} \cr & {\text{a}}:{\text{b}} = 65:550 \cr & \,\,\,\,\,\,\,\,\,\,\,\, = 13:110 \cr} $$