A certain sum is invested at simple interest at 18% p.a. for two years instead of investing at 12% p.a. for the same time period. Therefore the interest received is more by Rs. 840. Find the sum?

One Answer on this Question

1. let x be sum.
   SI of 18% for 1 year= x*18/100=0.18x;
   SI of 18% for 2 years is 0.36x;

   SI of 12% for 1 year= x*12/100=0.12x;
   SI of 12% for 2 years is 0.24x;

   Given, 0.36x-0.24x=840
   0.12x=840
   x=840/0.12=7000.

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