Simple interest of first year is Rs. 2700 and the difference of C.I s S.I of 2 year is Rs. 405 find the sum of money. एक वर्ष का साधारण ब्याज 2700 रूपयें है और दो वर्ष के चक्रवृद्धि ब्याज और साधारण ब्याज का अन्तर 405 रूपयें हैं मूलधन ज्ञात कीजिए।

Simple interest for first year is Rs. 2700, so annual interest rate on principal P is 2700. For compound interest, the extra interest in year 2 comes from interest on the first year's interest: (2700 × r/100) = 405. Solving gives r = 15%. Then 2700 = P × 15/100 gives P = Rs. 18000. Option A (Rs. 16000) and B (Rs. 19600) result from incorrect rate calculations.