SI for 1 year = Rs 400, S.I for 2 years = 2 × 4 00 = Rs 800 Using formula for 2 years, Rate = 2 × (CI - SI)/SI × 100 Rate = (2 × 20/800) × 100 = 5% Now, PR2/1002= CI - SI P × 5 2/ 100 2= 20 Principal = Rs 8,000 So amount after 3 years = 8000 [1 + 5/100]3= Rs 9261 C.I = 9261 - 8000 = Rs 1261