The bankers discount of a certain sum of money is Rs. 36 and the true discount on the same sum for the same time is Rs. 30. The sum due is:	Select.
A) 140  B) 150  C) 160  D) 170  E) 180

Rationale: "sum = ( b . d * t . d ) / ( b . d - t . d ) ( 36 * 30 ) / 36 - 30 ; 180 answer : e"
Answer: E