The Simple interest and the true discount and the true discount on a certain sum for a given time and at a given rate are Rs. 85 and Rs. 80 respectively. The sum is :  Choose the correct choice from the following options:  A) Rs. 1800  B) Rs. 1450  C) Rs. 1360  D) Rs. 6800  E) None
Solution   Sum =S.I xT.D./ ( S.I ) - ( T.D. ) = 85x80/85 - 80 = Rs. 1360.   Answer Rs. 1360
<result>C</result>
The Simple interest and the true discount and the true discount on a certain sum for a given time and at a given rate are Rs. 85 and Rs. 80 respectively. The sum is :