1) The difference between simple and compound interest on a certain sum of money for 3 years at 10% p.a. is Rs. 15.50. Find the sum. A) Rs.300 B) Rs.400 C) Rs.500 D) Rs.1000 E) Rs.800 Answer: Option CExplanation:The difference in C.I. and S.I. for 3 years is given by C.I.−S.I =P{(R100)3 +3(R100)2} ⇒1512 =P{(10100)3 +3(10100)2} ⇒312 =P[11000+3100] P =312×100031 = Rs. 500.