7th Grade Math

(Marvins-Underground-K-12) #1

Applying Percents (continued)


Sales Tax and Tips (Lesson 3C)
Find the total cost to the nearest cent.


  1. $12 haircut; 15% tip

  2. $48 dinner; 18% gratuity

  3. RESTAURANTS A restaurant bill comes to
    $42.75. Find the total cost if the tax is 6%
    and a 15% tip is left on the amount after
    the tax is added.


EXAMPLE 8 Raymond wants to tip the
server for his dinner. If the dinner costs $24
and he wants to give the server a 15% tip,
what is the total cost?

(^) decimal.15% of 24 = 0.15 × 24 Write 15% as a
= 3.60 The tip is $3.60.
$24.00 + 3.60 = $27.60 Add the tip and cost of
the dinner.
The total cost is $27.60.
Discount (Lesson 3D)
Find the sale price to the nearest cent.



  1. $45 roller blades; 20% discount

  2. $15 T-shirt; 25% discount

  3. ELECTRONICS A new


$30$30

radio is priced at $30.
The store has an
end-of-year sale and
all their items are
40% off. What is the
sale price of the radio?

EXAMPLE 9 A pair of shoes normally
costs $40. This week they are on sale for
20% off. What is the sale price of the shoes?
20% of 40 0.20 × 40 Write 20% as a decimal.
= 8.00 The discount is $8.00.
$40 - $8 = $32 Subtract the discount
from the cost.
The sale price is $32.

Financial Literacy: Simple Interest (Lesson 3E)
Find the interest earned to the nearest cent
for the principal, interest rate, and time.


  1. $475, 5%, 2 years


Find the interest paid to the nearest cent for
the loan balance, interest rate, and time.


  1. $3,200, 8%, 4 years

  2. SAVINGS Aleta deposited $450 into a
    savings account earning 3.75% annual
    simple interest. How much interest will
    she earn in 6 years?


EXAMPLE 10 Find the interest earned on
$400 at 9% for 3 years.
I = prt Simple interest formula
I = 400 · 0.09 · 3 p = $400, r = 0.09, t = 3
I = 108 Simplify.
The interest earned is $108.

Lesson 3

Chapter Study Guide and Review 369

366_370_C06_SGR_895130.indd 369 12/30/09 4:12 PM

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