Simple interest accrued on an amount in 8 yr @ 12 % per annum is Rs 5520 What is the principal amount ?

A sum become Rs. 10,650 in 5 years and Rs.11076 in 6 years at simple interest. What is the sum?

A person borrows 5,000 for 2 years at 4 % per annum simple interest. He immediately lends it to another person at $$6{1\over 4}\%  $$ per annum simple interest for 2 years. His gain in this transaction is 

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?

The difference of simple interest from two banks on ₹8,000 in 3 years is ₹800. If the rate of interest per annum in two banks are R1 and R2, then what is the value of R1 - R2? (Where R1 > R2)

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?

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. 

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?