S.I & C.I

Simple interest

interest paid on the principal alone.

Compound interest

interest calculated on both the principal and the accrued interest.

Interest

extra money we need to pay.

Rate

percentage at which we have to pay

Principle

Amount which we have got

SI formula

S.I = (P * N * R) / 100
P=(S.I * 100) /(N *R)
N=(S.I * 100) /(P *R)
R=(S.I * 100) /(N *R)

S.I= Simple Interest
P= Principle
N= no. of years
R= Rate of interest.

Compound Interest Formula

Amount= p * (1 + r/100) ^ n

p=Principle
r= rate of interest
n= number of years

When the interest is compound half - yearly then

Amount = p * (1 + r/( 2 *100) ) ^ ( 2* n)

For different rate of interest we have the formula as

Amount = p * (1 + r1/100) * (1 + r2/100) * (1 + r3/100)

C.I = Amount - Principle
C.I= compound interest