If 3A = 5B and 4B = 6C, then A : C equal to -

$$\eqalign{ & = {\text{3A}} = {\text{5B and 4B}} = {\text{6C}} \cr & \Rightarrow \frac{{\text{A}}}{{\text{B}}} = \frac{5}{3}{\text{ and }}\frac{{\text{B}}}{{\text{C}}} = \frac{6}{4} = \frac{3}{2} \cr & \Rightarrow \frac{{\text{A}}}{{\text{C}}} = \left( {\frac{{\text{A}}}{{\text{B}}} \times \frac{{\text{B}}}{{\text{C}}}} \right) = \frac{5}{3} \times \frac{3}{2} = \frac{5}{2} \cr & \Rightarrow {\text{A}}:{\text{C}} = {\text{5}}:{\text{2}} \cr} $$