The simple interest and the true discount on a certain sum for a given time and at a given rate are Rs. 85 and Rs. 75 respectively. The sum is:	Select the correct option.
A) 1360 B) 637.5 C) 1600 D) 1800 E) None
Sol.   Sum = S.I. * T.D. / (S.I)-(T.D.) = 85 * 75 / (85 - 75) = Rs.637.5.   Answer 637.5
<result>B</result>
The simple interest and the true discount on a certain sum for a given time and at a given rate are Rs. 85 and Rs. 75 respectively. The sum is: