Discount (True and Banker’s) question bank (Quantitative Aptitude)

$A$ bill for $Rs. 8000$ is drawn on September $19$ for $6$ months. It is discounted on January $8$ at $10\%$. Find the banker's discount,true discount,banker's gain,and the money that the holder of the bill receives (in $Rs.$).

The difference between the simple interest and the true discount on a certain sum of money for $2$ years at $15 \%$ per annum at simple interest is $Rs. 45$. Find the sum (in $Rs.$).