Compound Interest Important Formulas - Aptitude Questions and Answers

Let Principal = P, Rate = R% per annum, Time = n years.

When interest is compound Annually:

Amount = P

1 +

100

When interest is compounded Half-yearly:

Amount = P

1 +

(R/2)

100

When interest is compounded Quarterly:

Amount = P

1 +

(R/4)

100

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

years

Amount = P

1 +

100

1 +

100

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

Then, Amount = P

1 +

R₁

100

1 +

R₂

100

1 +

R₃

100

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

Present Worth =

1 +

100