Study Guide and Review - Percent
State whether the sentence is true or false . If false , replace the underlined word or number to make a
true sentence.
The sale price of a discounted item is the regular price minus the discount.
The sentence is true because the sale price is the regular price minus the discount.
A ratio that compares the change in quantity to the original amount is called the percent of change.
The sentence is true because the percent of change is a ratio that compares the change in quantity to the original
amount.
A percent proportion compares part of a quantity to the whole quantity using a percent.
The sentence is true because one of the ratios in the percent proportion compares part of a quantity to the whole
quantity, while the other ratio is an equivalent percent written as a fraction with the denominator of 100.
The formula for simple interest is I = prt .
The sentence is true because I = prt is the formula that is used for simple interest.
One way to find the total bill with tip is to add the percent of tip to 10%.
The sentence is false because one method for finding the total bill is to add the percent of tip to 100% of the bill
before tip.
The equation part = percent whole is known as the principal equation.
The sentence is false because the equation part = percent whole is the percent equation.
The principal is the amount of money deposited or borrowed.
The sentence is true because the principal is the amount of money deposited or borrowed.
A tax is the amount by which the regular price of an item is reduced.
The sentence is false because the discount is the amount by which the regular price of an item is reduced.
To find a percent of increase, compare the amount of the increase to the new amount.
The sentence is false because finding a percent of increase involves comparing the amount of the increase to the
original amount.
If the new amount is greater than the original amount, then the percent of change is percent of decrease.
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To find a percent of increase, compare the amount of the increase to the new amount.
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Study
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original amount.
If the new amount is greater than the original amount, then the percent of change is percent of decrease.
The sentence is false because if the new amount is greater than the original amount, then the percent of change is
percent of increase.
Find the number. Round to the nearest tenth if necessary.
6 is what percent of 120?
Let n% represent percent.
So, 6 is 5% of 120.
Find 0.8% of 35.
Let p represent the part.
So, 0.3 is about 0.8% of 35.
What percent of 375 is 40?
Let n% represent percent.
So, 40 is about 10.7% of 375.
SOCCER A soccer team lost 30% of their games. If they played 20 games, how many did they win?
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20 games is the whole. Let p represent the part.
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Study Guide and Review - Percent
So, 40 is about 10.7% of 375.
SOCCER A soccer team lost 30% of their games. If they played 20 games, how many did they win?
20 games is the whole. Let p represent the part.
So, the team lost 6 of the 20 games. Subtract 6 from 20 to find how many games they won.
20 6 = 14
So, they won 14 games.
Find the percent of change. Round to the nearest whole percent if necessary. State whether the percent
of change is an increase or decrease.
original: 172
new: 254
Find the amount of change.
254 172 = 82
Find the percent of change.
The percent of change is about 48%. Since the percent is positive, this is a percent of increase.
original: $200
new: $386
Find the amount of change.
$386 $200 = $186
Find the percent of change.
The percent of change is 93%. Since the percent is positive, this is a percent of increase.
original: 75
new: 60
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Find the amount of change.
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Study Guide and Review - Percent
The percent of change is 93%. Since the percent is positive, this is a percent of increase.
original: 75
new: 60
Find the amount of change.
60 75 = 15
Find the percent of change.
The percent of change is 20%. Since the percent is negative, this is a percent of decrease.
original: $49.95
new: $54.95
Find the amount of change.
$54.95 $49.95 = $5
Find the percent of change.
The percent of change is about 10%. Since the percent is positive, this is a percent of increase.
COMICS Tyree bought a collectible comic book for $49.62 last year. This year, he sold it for $52.10. Find the
percent of change of the price of the comic book. Round to the nearest percent.
Find the amount of change.
$52.10 $49.62 = $2.48
Find the percent of change.
The percent of change is about 5%. Since the percent is positive, this is a percent of increase.
Find the total cost to the nearest cent.
$12 haircut; 15% tip
Method 1: Add the tip to the regular price.
Find the tip.
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Study Guide and Review - Percent
The percent of change is about 5%. Since the percent is positive, this is a percent of increase.
Find the total cost to the nearest cent.
$12 haircut; 15% tip
Method 1: Add the tip to the regular price.
Find the tip.
Add the tip to the regular price.
Method 2: Add the percent of tip to 100%.
100% + 15% = 115%
The total cost is 115% of the bill.
The total cost of the haircut with tip is $13.80.
$48 dinner; 18% gratuity
Method 1: Add the gratuity to the regular price.
Find the gratuity.
Add the gratuity to the regular price.
Method 2: Add the percent of gratuity to 100%.
100% + 18% = 118%
The total cost is 118% of the bill.
The total cost of the dinner with gratuity is $56.64.
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.
Find the tax.
Add the tax to the regular price.
Add the tip to the total with tax.
The total cost with tax and tip is $52.12.
Find the sale price to the nearest cent.
$45 Manual
roller blades;
20%
discount
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Method 1: Subtract the discount from the regular price.
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Study Guide and Review - Percent
The total cost with tax and tip is $52.12.
Find the sale price to the nearest cent.
$45 roller blades; 20% discount
Method 1: Subtract the discount from the regular price.
Find the discount.
Subtract the discount from the regular price.
Method 2: Subtract the discount from 100%.
100% 20% = 80%
The sale price is 80% of the regular price.
The sale price of the roller blades is $36.
$15 T-shirt; 25% discount
Method 1: Subtract the discount from the regular price.
Find the discount.
Subtract the discount from the regular price.
Method 2: Subtract the discount from 100%.
100% 25% = 75%
The sale price is 75% of the regular price.
The sale price of the T-shirt is $11.25.
ELECTRONICS A new 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?
Method 1: Subtract the discount from the regular price.
Find the discount.
Subtract the discount from the regular price.
Method 2: Subtract the discount from 100%.
100% 40% = 60%
The sale price is 60% of the regular price.
The sale price of the radio is $18.
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100% 25% = 75%
The sale price is 75% of the regular price.
Study Guide and Review - Percent
The sale price of the T-shirt is $11.25.
ELECTRONICS A new 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?
Method 1: Subtract the discount from the regular price.
Find the discount.
Subtract the discount from the regular price.
Method 2: Subtract the discount from 100%.
100% 40% = 60%
The sale price is 60% of the regular price.
The sale price of the radio is $18.
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