The bankerâ€™s discount of a certain sum of money is Rs. 90 and the true discount on the same sum for the same time is Rs. 60. The sum due is	Pick.
A) 210  B) 180  C) 360  D) 450  E) none

Rationale: "sol . sum = b . d . * t . d . / b . d . - t . d . = rs . [ 90 * 60 / 90 - 60 ] = rs . [ 90 * 60 / 30 ] = rs . 180 answer b"
Answer: B