Simple Interest and Compound Interest formulas:

1. Compound Interest formulas:
   
   
   Let Principal = P, Rate = R% per annum, Time = n years.
2. When interest is compound Annually:

   Amount = P		1 +	R		n
   			100

3. When interest is compounded Half-yearly:

   Amount = P		1 +	(R/2)		2n
   			100

4. When interest is compounded Quarterly:

   Amount = P		1 +	(R/4)		4n
   			100

5. When interest is compounded Annually but time is in fraction, say 3 years.

   Amount = P		1 +	R		3	x		1 +	R
   			100						100

6. When Rates are different for different years, say R₁%, R₂%, R₃% for 1^st, 2^ndand 3^rd year respectively.

   Then, Amount = P

   1 +

   R1

   1 +

   R2

   1 +

   R3

   .

   100

   100

   100

7. Present worth of Rs. x due n years hence is given by:

   Present Worth =	x	.
   	1 + R 100

   
   
   
   Simple Interest:
   
   
   
   
   1. Principal:
      The money borrowed or lent out for a certain period is called the principal or thesum.
   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 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 =

      100 x S.I.

      and T =

      100 x S.I.

      .

      R x T

      P x T

      P x R