Main Idea and New Vocabulary
Example 1: Find the Total Cost
Example 2: Find the Tip
Example 3: Real-World Example
• Solve problems involving sales tax and tips.
• sales tax
• tip
• gratuity
Find the Total Cost
SOCCER A limited-edition soccer ball costs $30,
and the sales tax is 6%. What is the total cost?
Method 1
Add sales tax to the regular price.
First, find the sales tax.
6% of $30 = 0.06  30
= 1.80
Write 6% as a decimal.
The sales tax is $1.80.
Next, add the sales tax to the regular price.
$30.00 + $1.80 = $31.80
Find the Total Cost
Method 2
Add the percent of tax to 100%.
100% + 6% = 106%
Add the percent of tax
to 100%.
The total cost is 106% of the regular price.
106% of $30 = 1.06  $30
= $31.80
Write 106% as a
decimal.
Multiply.
Answer: The total cost of the soccer ball is $31.80.
BOOKS A book cost $22 and the sales tax is 8%.
What is the total cost?
A. $14.00
B. $20.24
C. $23.76
D. $30.00
Find the Tip
TIPPING Whitney’s bill at a diner came to $26.00.
What would she pay if she included a 20% tip?
Method 1
Add the tip to the regular price.
First, find the tip.
20% of $26.00 = 0.20  26
= 5.20
Write 20% as a decimal.
The tip is $5.20.
Next, add the tip to the regular price.
$26.00 + $5.20 = $31.20
Find the Tip
Method 2
Add the percent of tip to 100%.
100% + 20% = 120%
Add the percent of tip
to 100%.
The total cost is 120% of the regular price.
120% of $26 = 1.20  $26 Write 120% as a
decimal.
= $31.20
Multiply.
Answer: The total cost of the bill with tip is $31.20.
TIPPING Dave’s lunch bill came to $11.00. What
would he pay if he included a 15% tip?
A. $11.15
B. $12.65
C. $16.65
D. $25.00
MANICURE A manicure costs $18. The sales tax
is 8.25%. You want to tip 20%. Is $22 sufficient to
cover the manicure, tax, and tip?
Sales tax is 8.25% and the tip is 20%, so together
they will be 28.25%.
28.25% of $18 = 0.2825  18
= 5.09
$18 + $5.09 = $23.09
Write 28.25% as a
decimal.
Multiply.
Add.
Answer: No, $22 is not sufficient to cover the
manicure with tax and tip.
MASSAGE A massage costs $55. The sales tax
is 7%. You want to tip 15%. Is $68 sufficient to
cover the manicure, tax, and tip?
A. Yes, the massage with tax and tip is $67.10, so
$68 is sufficient.
B. No, the massage with tax and tip is more
than $68.