Banker's Discount - General Questions

The banker's discount on a sum is Rs. 389.76 and the true discount is Rs. 336. What is the sum due?

What is the banker's discount on a bill of Rs. 8,900 due 8 months hence at 8% per annum?

The true discount on a bill due 3 year(s) hence at 5% per annum is Rs. 240. What is the banker's gain?

The banker's discount on a sum is Rs. 960 and the true discount is Rs. 800. What is the sum due?

The true discount on a bill due 2 year(s) hence at 5% per annum is Rs. 330. What is the banker's gain?