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

Answer: Option D

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