A person invested some amount at the rate of 12 % simple interest and a certain amount at the rate of 10 % simple interest for 1 year. He received yearly interest of Rs. ₹ 130, but if he had interchanged the amount invested, he would have received 4 more as interest. How much did he invest at 12 % simple interest? 

Any money at the rate of simple interest becomes Rs 1143 in 3 years and Rs 1305 in 5 years Find the rate of principal and interest.

At what simple rate of interest a sum is double in 8 years?

The simple interest on a sum of money for 3 years is ₹240 and the compound interest on the same sum, at the same rate  for 2 years is ₹170. The rate of interest is 

A sum becomes 5 times of itself in 3 years at compound interest (interest is compounded annually). In how many years will the sum becomes 125 times of itself?

The principal which gives ₹ 1 interest per day at a rate of 5 % simple interest per annum is 

At what annual percentage rate, 10 years of simple interest on an amount will be $$ {2\over 5}$$ of the addition?

A certain sum doubles in 7 years at simple interest. The same sum under the same interest rate will become 4 times in how many years.: