If the simple interest on a certain sum of money for 2 years in one fifth of the Principal, then find rate of interest per annum. 

At the rate of 8 % simple annual interest, if an amount becomes Rs. 819 in 3 years and 3 months, then what was the original amount?

A sum of ₹ 3000 yields an interest of ₹ 1080 at 12% per annum simple interest in how many years ?

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? 

A certain sum of Rs.4200 becomes Rs5523 at 11% p.a simple interest in a certain time. What is the simple interest on the sum of Rs. 4800 at the same rate and in same time period?

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?

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

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