Facilitated by…… Anna Deroscar
Briarcliffe College
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68.
Percent Notation
Percent and Fraction Notation
Solving Percent Problems
Using Percent Equations
Solving Percent Problems
Using Percent Proportions
Applications of Percents
Sales Tax, Commission and
Discount
Simple and Compound
Interest
Interest Rates on Credit Cards
and Loans

Key Words Translation
“Of”: translates to
“multiplication”
“What”: translates to
“any letter”.
“Is”: translates to: “=
sign”
% translates to: “
Examples:
$39 is what percent of $50?

Proportion Set-Up

Proportion Set-Up
Example:
a)
Example:
a) $24 is what percent of $96?
What percent of $80 is $60?
Example:
a)
From 1964 to 1997, of 133 panda cubs
born in captivity, only 90 lived to be
one month old. What percent lived to
be one moth old?
a)
In 1999, Mark Edwards of the Sand
Diego Zoo developed a nutritional
formula on which 18 of 20 newborns
lived to be one month old. What
percent lived to be one month old?
Sales Tax
Sales tax= Sales tax rate x Purchase Price
Total Price = Purchase Price + Sales Tax

Example:
The sales tax rate in New Jersey is 6%.
a) How much sales tax would be charged
on a copy of John Grisham’ s novel “A
Painted House, which sells for $27.95?
b)
What is the total cost to purchase the
book?
Round to the
nearest
hundredth, we
are dealing with
money
Commission= Commission rate x Sales
Commission rate=
Example:
a) Katrina’s commission rate is 6%.
What is the commission from the
sales of $45,000 worth of furnaces
Example:
a)
Mitchell earns $120 selling $2400
worth of television sets in a
consignment shop. What is the
commission rate

Discount and Sales Price
Discount= Rate of discount x Original Price
Sale Price= Original price - Discount
Example:
a) Jennifer is going to purchase a Gucci Bag
during the Black Friday week? The original
price is $2000 dollars but she has a
discount coupon of 40 %. What is her
discount?
b) What will be Jennifer’s total cost to
purchase the her Gucci Bag?

Simple Interest Formula
What is the simple interest for $200
invested at an interest rate of 7.7%
for ½ year?
I= Simple interest
P= principal
R= rate
T = time (years)

Compound Interest
Formula
Find the amount in an account if
$40,000 is invested at 7.7% semiannually for 4 year?
A= Compound Interest Formula
P= principal
r= rate
t = time (years)
n = how its compound

After graduating the balance on Ricky’s Stafford loan is
$38,970. To pay off the loan at 3.37%, he will make 120
payments of approximately $382.99 each.
◦ Find the amount of interest and the amount applied to reduce
the principal in the first payment.
◦ If the interest rate were 5.4%, he would make 120 monthly
payments of approximately $421 each. How much more of the
first payment is interest if the loan is 5.4% rather than 3.7%?
◦ Compare the total amount of interest on the loan at 3.37% with
the amount on the loan at 5.4%. How much more would Ricky
pay on the 5.4% loan than on the 3.37% loan