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. 78 respectively. The sum is:
Choices: A) 1360 B) 1450 C) 1600 D) 947 E) None
Sol.   Sum = S.I. * T.D. / (S.I)-(T.D.) = 85 * 78 / (85 - 78) = Rs.947.   Answer 947
<result>D</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. 78 respectively. The sum is: