[latexpage]
Simple interest
$SI = P*R*T/100$
P= principal amount
R = rate/unit
T = time/year month day etc.
Compound interest
$CI = P(1+\frac{R}{100})^n$
P= principal amount
R= rate/unit
T= time unit
Where rate are difference for different unit or time.
Than $C.I = p(1+\frac{R1}{100}) (1+\frac{R2}{100}) (1+\frac{R3}{100}) ……….$
Present worth of Rs x lac in year hence is given by present worth=
$\frac{x}{(1+\frac{r}{100})^n}$