1) A sum of money amounts to Rs. 5,200 in 5 years and to Rs. 5,680 in 7 years at simple interest. The rate of interest per annum is A) 3% B) 4% C) 5% D) 6% E) 5% Answer: Option DExplanation:P+S.I. for 5 years =5,200 ---(1) P+S.I. for 7 years =5,680 ---(2) (2) - (1) ⇒S.I. for 2 years =480 S.I. for 1 year =240 From equation (1) P+5×240 =5200 ⇒P =5200−1200 = Rs. 4000 R =100×SIP×N =100×2401×4000 = 6%.