The present worth of a certain bill due sometime hence is Rs. 400 and the true discount is Rs. 20. What is the banker's discount?
Choose the most appropriate option.
A) Rs. 19  B) Rs. 22  C) Rs. 20  D) Rs. 21  E) None of these
Explanation :   BG = (TD)2/PW=202/400= Rs. 1   BG = BD – TD   =&gt; 1 = BD - 20   =&gt; BD = 1 + 20 = Rs. 21 Answer : Option Rs. 21
<result>D</result>
The present worth of a certain bill due sometime hence is Rs. 400 and the true discount is Rs. 20. What is the banker's discount?