Simple Interest Formulas, Shortcuts and Study Material

Simple Interest Formulas - Page 2
Simple Interest Online Test - Page 3
Simple Interest Video Lecture - Page 4

Interest is the cost of borrowing money.An interest rate is the cost stated as a percent of the amount borrowed per period of time, usually one year.

Simple Interest: Simple interest is calculated on the original principal only.Accumulated interest from prior periods is not used in calculations for the following periods. Simple interest is normally used for a single period of less than a year, such as 30 or 60 days.
Simple interest =$(\frac{P\times R\times T}{100})$

P = principal (original amount borrowed or loaned)
R = interest rate for one period
T = number of periods

Principal: The money borrowed or lent out for a certain period is called the principal or the sum.

Interest: Extra money paid for using other's money is called interest.

Simple Interest (S.I.): If the interest on a sum borrowed for certain period is reckoned uniformly, then it is called simple interest.

Let Principal = P, Rate = R% per annum (p.a.) and Time = T years. Then

(i) Simple interest=$(\frac{P\times R\times T}{100 })$

(ii) P=$\left [ \frac{100\times S.I}{R\times T} \right ] ;R=\left [ \frac{100\times S.I}{T\times R} \right ] and\, T=\left [ \frac{100\times S.I}{P\times R} \right ]$