The banker's gain on a sum due 6 years hence at 12% per annum is Rs. 540. What is the banker's discount?

$$\eqalign{ & TD = \frac{{BG{\text{ }} \times 100}}{{TR}} \cr & \,\,\,\,\,\,\,\,\,\,\, = \frac{{540 \times 100}}{{6 \times 12}} \cr & \,\,\,\,\,\,\,\,\,\,\, = \frac{{90 \times 100}}{{12}} \cr & \,\,\,\,\,\,\,\,\,\,\, = \frac{{15 \times 100}}{2} \cr & \,\,\,\,\,\,\,\,\,\,\, = {\text{Rs}}{\text{.}}\,750 \cr & BG = BD - TD \cr & \Rightarrow 540 = BD - 750 \cr & \Rightarrow BD = 540 + 750 \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 1290 \cr} $$