7th Grade Math

356 Percent

Sales Tax and Discount Sales Tax and Discount

If both are represented as

percents, sales tax is a

percent of increase and

discount is a percent of

decrease.

Find the Sale Price

BOOGIE BOARDS A boogie board that has a regular price of $69 is

on sale at a 35% discount. What is the sale price with 7% tax?

Step 1 Find the amount of the discount.

35% of $69 = 0.35 · $69 Write 35% as a decimal.

= $24.15 The discount is $24.15.

Step 2 Subtract the discount from the regular price.

$69 - $24.15 = $44.85

Step 3 The percent of tax is applied after the discount is taken.

7% of $44.85 = 0.07 · 44.85 Write 7% as a decimal.

= 3.14 The tax is $3.14.

Add the tax to the sale price of the boogie board.

$44.85 + $3.14 = $47.99

The sale price of the boogie board including tax is $47.99.

b. MUSIC A CD that has a regular price of $15.50 is on sale at a

25% discount. What is the sale price with 6.5% tax?

Find the Original Price

CELL PHONES A cell phone is on sale for 30% off. If the sale price

is $239.89, what is the original price?

The sale price is 100% - 30% or 70% of the original price.

Words

Variable

Equation

$239.89 is 70% of what price?

Let p represent the original price.

$239.89 = 0.7 × p

239.89 = 0.7p Write the equation.

_239.89

0.7

=

0.7p

_

0.7

Divide each side by 0.7.

342.70 = p Simplify.

The original price is $342.70.

c. Find the original price if the sale price of the cell phone is $205.50.

Percent Equation Percent Equation

Remember that in the

percent equation, the

percent must be written as

a decimal. Since the sale

price is 70% of the original

price, use 0.7 to represent

70% in the percent

equation.

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