A certain sum is lent at 4% per annum for 3 years 8% per annum for next 4 years and 12% per annum beyond 7 years. If for a period of 11 years, the simple interest obtained is Rs. 27,600, then the sum is (in Rs.):

Solution (By Examveda Team)

$$\eqalign{ & 27600 = \frac{{P\left( {3 \times 4 + 4 \times 8 + 4 \times 12} \right)}}{{100}} \cr & \frac{{27600 \times 100}}{{12 + 32 + 48}} = P \cr & P = \frac{{27600 \times 100}}{{92}} \cr & P = {\text{Rs}}{\text{. }}30000 \cr} $$