SIMPLE INTEREST -> IMPORTANT FORMULAE

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

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

3. Simple Interest (S.I.) : If the interest on a sum borrowed for a 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) S.I. = [P * R * T / 100] 

(ii) P = [100 * S.I. / R * T] 

R = [100 * S.I / P * T] and T = [100 * S.I. / P * R]