Applications with Percents. Objective: 7.1.01 Develop and use ratios, proportions, and percent to...
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Transcript of Applications with Percents. Objective: 7.1.01 Develop and use ratios, proportions, and percent to...
Applications with Percents
Applications with PercentsObjective:7.1.01 Develop and use ratios, proportions, and
percent to solve problems
Essential Question: How can I apply my understanding
of percents to make more informed shopping decisions?
What is the best “DEAL” or Value?
Vocabulary:Sales Tax: an additional amount of money charged on the
items people buy; the government uses this money to operate the country.
(Not all countries, states or cities have a tax)!Some items are taxed at different rates.
Discount: the amount of money (or percent) by which the regular price of an item is reduced.
Tip: also known as gratuity, is money given to a person who provides a service, and is added to the cost of that service. (In some places it is automatically added!)
Applications with Percents
Real World Choices:Sam has a dilemma. He wants to purchase a game
but cannot decide where to buy it.
Target is selling them for $399.99 with a 15% discount.
Best Buy is selling them for $375.99 but only a 10% discount.
Where should Sam buy his game?
Applications with Percents
But What About If…
Applications with Percents
Real World Example:Target was selling them for $399.99 with a 20%
discount.
Best Buy was selling them for $375.99 and a 15% discount.
Applications with Percents
COMPARE PURCHASE DECISIONS
Store-1 Store-2
Original Cost $399.99 $375.99
Discount Rate 15% 10%
Amount of DiscountHint: Round
.15 x 399.99
.15 x 400 =.1 x 375.99.1 x 376 =
$ Discount $60 $ 37.60
New Price =Original - Discount
400 – 60 = $360
376 – 37.60= $338.4
Applications with PercentsExample 1: Finding Total Cost
A calculator costs $90 and the sales tax is 6%. What is the total cost?
$95.40
Total Cost = Original Cost + Sales TaxFirst calculate the Sales Tax6% OF $90
= 0.06 x 90
$5.40
Total Cost $90.00 + $5.40Total Cost $95.40
Applications with PercentsExample 2: Finding Total Cost
A laptop costs $475 and the sales tax is 7½%. What is the total cost?
$510.63
Total Cost = Original Cost + Sales TaxFirst calculate the Sales Tax
7½% OF $4750.075 x 475
$35.63
Total Cost $475.00 + $35.63Total Cost $510.63
Another way to think about: TOTAL COSTTotal Cost = $Original + $TAX
6% Tax on an Original price of $90. .06 x 90 = $5.40 taxSO: 90 + 5.40 = $95.40
OR:
Total Cost = 90 (1.06)
Total Cost = ORIGINAL x (1 + Rate)
$95.40
Applications with PercentsExample 3: Finding Sale Price
A snowboard has a regular price of $169 but is on sale for 35% off. What is the sale price?
$109.85
Sale Price = Original Cost – DiscountFirst calculate the discount
= 35% OF $169
0.35 x 169$59.15
Total Cost $169.00 – $59.15Total Cost $109.85
Applications with PercentsExample 4: Finding Sale Price
A new coat has a regular price of $185 but is on sale for 33% off. What is the sale price?
$123.95
Sale Price = Original Cost – DiscountFirst calculate the Discount
33% OF $185 0.33 x 185
$61.05
Total Cost $185.00 – $61.05Total Cost $123.95
Another way to think about Sale PriceSales Price = Original - Discount
20% Discount off an Original price of $180. .2 x 180 = $36SO: 180 – 36 = $144
IF the DISCOUNT was 20% , (Percent means 100) SO, that means the Sales Price is
80% of the Original!.8 x 180 = $144.00
Applications with PercentsExample 5: Finding Total Cost
A meal at Pizza Inn cost $25.85. The tax is 8% and Mr. Williams wanted to leave a 15% tip.
What was the TOTAL AMOUNT of the meal?
$31.80
Total Cost = Cost of Meal + Tax + TipFirst calculate
the tax8% OF $25.850.08 x 25.85
$2.07
Next calculate the tip
15% OF $25.850.15 x 25.85
$3.88
25.85$2.07$3.88
Applications with PercentsExample 6: Finding Percent of Discount
An electric guitar was originally $299.95 but on sale for $179.99. What is the percent of discount?
40%
Discount = Original Cost – Sale Price= $299.95 – 179.99= $119.96
Use the Percent Proportion To
Calculate Percent of Discount
ISOF
%100
= =
Applications with PercentsExample 7: Finding Percent of MarkupIn the last 6 months the average price for a gallon of
unleaded gasoline has risen from $2.85 to $3.10. What is the percent of markup?
8.7%
Markup = New Price – Old Price= $3.10 – $2.85= $0.25
Use the Percent Proportion To
Calculate Percent of Discount
ISOF
%100
.0877 = 8.7%
When Calculating Percents of Markup and Discount:
Applications with Percents
Always Remember…You can use the percent proportion or the percent of change formula to make your calculations.
If you choose to use the percent proportion you have to calculate the change first and use that as your IS and use the original price as your OF.
PRACTICE with TAX and DISCOUNTItem Original
CostTax or Discount Rate
Amount of Tax or Discount
Total Cost
CD Player $99.00 5% tax
Computer $1,500.00 25% Discount
Skateboard 119.50 20% Off
Notebook $4.30 8% Tax
Book $24.95 4.5% Tax
Sweater $39.60 40% Discount
Independent Practice:Determine the final cost for each example:
1. $99 CD Player, 5% Tax2. $1,500 Computer, 25% Discount3. $119.50 Skateboard, 20% Off4. $4.30 Notebook, 8% Tax5. $24.95 Book, 4.5% Tax6. $39.60 Sweater, 40% Discount
Applications with Percents
= $103.95= $1125.00
= $$95.60= $4.64
= $26.07= $23.76
Summary:Applications with Percents
Always Remember…
1) Discounts or Sales are subtracted from the original cost of an item
2) Tax is added to the cost of an item
3) To determine the Percent of a Discount or Percent of Markup use the percent proportion or percent change formulas
Applications with PercentsHOMEWORK