The true discount on a bill of Rs. 540 is Rs. 90. The banker's discount is:

Answer: Option B

$$\begin{array}{rl}& \text{P}\text{.W}\text{.}=Rs.\left(540-90\right)\\ & =Rs.450\\ & \therefore \text{S}\text{.I}\text{.}\text{on}Rs.450=Rs.90\\ & \text{S}\text{.I}\text{.}\text{on}Rs.540\\ & =Rs.\left(\frac{90}{450}\times 540\right)\\ & =Rs.108\\ & \therefore \text{B}\text{.D}.=Rs.108\end{array}$$