Answer:
A. Simple interest is calculated on the principal, or original, amount of a loan. Compound interest is calculated on the principal amount and also on the accumulated interest of previous periods, and can thus be regarded as "interest on interest."
B. Simple interest=P×i×n
where: P=Principle
i=interest rate
n=term of the loan
Compound interest=[P(1+i)n]−P
Compound interest=P[(1+i)n−1]
where: P=Principle
i=interest rate in percentage terms
n=number of compounding periods for a year