Simple Interest

When money is loaned, the borrower usually pays a fee to the lender. this fee is called 'interest'. Simple interest or flat rate interest is the amount of interest paid each year in a fixed percentage of the amount borrowed or lent at the start.
The formula foe calculating simple interest is as follows:
Interest = Principal * Rate * Time

Illustration
A Student purchase a computer by obtaining a loan on simple interest. The computer cost Rs. 1,500 and the interest rate on the loan is 12 %. If, the loan is to be paid back on weekly installments over two years,,
Interest: =  (1,500*12*2)/100
             = Rs. 360
Total Repayments = Principal + Interest
                            = Rs. 1,500 + Rs.360
                            = Rs. 1,860
Weekly payment amount =        Total repayment       
                                          Loan period, T, in weeks
                                      = Rs. 1,860/(2*52)
                                      = Rs. 17.88 per week