Question : Sunita invested INR 12,000 on simple interest at the rate of 10% p.a. to obtain a total amount of INR 20,400 after a certain period. For how many years did she invest to obtain the above amount?

Question : John invested a sum of money at an annual simple interest rate of 10%. At the end of four years, the amount invested plus interest earned is Rs. 770. The amount invested was:

Question : On a certain sum of money, the simple interest for 2 years is Rs. 350 at the rate of 4% per annum. It was invested at compound interest at the same rate for the same duration as before, how much more interest would be earned?

Question : A person invested a sum of INR 10,500 at $x$% per annum at simple interest and a sum of INR 13,500 at $(x + 2)$% p.a. at simple interest. If the total interest earned on both investments for 3 years is INR 7,650, then the rate of interest on the first investment is:

Question : If the annual rate of simple interest increases from $11\%$ to $17 \frac{1}{2} \%$, a person's yearly income increases by Rs. 1,071.20. The principal amount invested (in Rs.) is: