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**Simple Interest Important formulas:**

**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 Intereest = (P x R x T /100 )

**(ii)**. P = (100 x S.I /R x T);

R = (100 x S.I /P xT). and T = (100 x S.I / P xR) .

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