How to work with percentages - HSPT Math
Card 0 of 532
Fifteen percent of the students in the classroom brought their lunch from home. If 9 students brought their lunch from home, how many students are in the classroom total?
Fifteen percent of the students in the classroom brought their lunch from home. If 9 students brought their lunch from home, how many students are in the classroom total?
You can think of the total number of students in the classroom as an unknown variable, 
.
You can set up an equation that includes 
and the information given. Normally in a percent problem, you would start with the total amount of something and multiply it by the percent to get the part of that total amount. You can set this up the same way, but the total amount is the missing information:
Total Amount x Percent = Part of Total Amount
You use 
to numerically represent 15 percent.
Now you can algebraically solve for 
, which will give you the total number of students in the class. You do this by dividing each side by 
.
Therefore there are 60 total students.
You can think of the total number of students in the classroom as an unknown variable,
You can set up an equation that includes
Total Amount x Percent = Part of Total Amount
You use
Now you can algebraically solve for
Therefore there are 60 total students.
Compare your answer with the correct one above
A class has 25 students. If 60% of them are boys, how many students are girls?
A class has 25 students. If 60% of them are boys, how many students are girls?
We know that 40% of the class are girls because 60% are boys. To express 40% as a fraction of the 25 total students, we set up a proportion to find the number of girls in the class.
When solving for 
, we find that there are 10 girls in the class.
We know that 40% of the class are girls because 60% are boys. To express 40% as a fraction of the 25 total students, we set up a proportion to find the number of girls in the class.
When solving for
Compare your answer with the correct one above
A store normally sells a certain coat for $40. For the holidays it offers a sale where the new price of the coat is now $30. What percent discount is the store selling the coat for?
A store normally sells a certain coat for $40. For the holidays it offers a sale where the new price of the coat is now $30. What percent discount is the store selling the coat for?
The coat is $10 cheaper than normal.
The coat is $10 cheaper than normal.
Compare your answer with the correct one above
Exactly 
of the plants in a garden are tomato plants. Which of the following could be the total number of plants in the garden?
Exactly
The total number of plants has to be divisible by 3. Of the answer choices, the only one that is divisible by 3 is 18. You can check this because numbers that are divisible have the sum of their digits also divisible by 3. For example,
which is divisible by 3, so 18 is divisible by 3.
The total number of plants has to be divisible by 3. Of the answer choices, the only one that is divisible by 3 is 18. You can check this because numbers that are divisible have the sum of their digits also divisible by 3. For example,
which is divisible by 3, so 18 is divisible by 3.
Compare your answer with the correct one above
If Suzie's birthday cake costs $15 and it is on sale for 25% off how much will she pay at the register?
If Suzie's birthday cake costs $15 and it is on sale for 25% off how much will she pay at the register?
To find the answer you must first convert the sales percentage to a decimal by moving the decimal left two places yielding 
Then multiply the total cost by the decimal 
.
We then subtract the sales number from the original cost to get the answer:
To find the answer you must first convert the sales percentage to a decimal by moving the decimal left two places yielding
Then multiply the total cost by the decimal
We then subtract the sales number from the original cost to get the answer:
Compare your answer with the correct one above
Susan has a coupon for 10% off any one item at her favorite department store. There is also a storewide sale of 50% off all purchases.
If Susan wants to by a shirt originally priced at $42, how much will she pay?
Susan has a coupon for 10% off any one item at her favorite department store. There is also a storewide sale of 50% off all purchases.
If Susan wants to by a shirt originally priced at $42, how much will she pay?
The storewide sale discounts the shirt by 50%:
Susan also has the 10% off coupon, so she's really paying 90% of the cost of the shirt:
The storewide sale discounts the shirt by 50%:
Susan also has the 10% off coupon, so she's really paying 90% of the cost of the shirt:
Compare your answer with the correct one above
The price of a suit after a 20% employee discount is $240.00. What is the original price?
The price of a suit after a 20% employee discount is $240.00. What is the original price?
Deducting a 20% discount is the same as charging 80% of the price, so $240.00 is 80% of the original price, which we call 
. Just solve this equation:
The suit originally cost $300.00
Deducting a 20% discount is the same as charging 80% of the price, so $240.00 is 80% of the original price, which we call
The suit originally cost $300.00
Compare your answer with the correct one above
Express 
% as a fraction in lowest terms.
Express
Put the percent over 100 and simplify as follows:
Note: all of these choices are equivalent to 
%; but only 
is in lowest terms.
Put the percent over 100 and simplify as follows:
Note: all of these choices are equivalent to
Compare your answer with the correct one above
There are 500 students at the high school. There are only two menu options: chicken or fish. If 15% of students ordered fish, how many students ordered chicken?
There are 500 students at the high school. There are only two menu options: chicken or fish. If 15% of students ordered fish, how many students ordered chicken?
If 15% of students ordered fish, then 85% of the students must have ordered chicken. Then multiply 85% or 
.
If 15% of students ordered fish, then 85% of the students must have ordered chicken. Then multiply 85% or
Compare your answer with the correct one above
The sales tax rate for a particular locality is 9%. How much will be paid after tax for $154.92 worth of groceries?
The sales tax rate for a particular locality is 9%. How much will be paid after tax for $154.92 worth of groceries?
Multiply the price of the groceries before tax - $154.92 - by the decimal equivalent of 9% , which is 0.09. Round this tax to the nearest hundredth (cents), then add to the price of the groceries.
Tax: 
Price after tax: 
Multiply the price of the groceries before tax - $154.92 - by the decimal equivalent of 9% , which is 0.09. Round this tax to the nearest hundredth (cents), then add to the price of the groceries.
Tax:
Price after tax:
Compare your answer with the correct one above
A laptop computer is on sale for 40% less than the original price. If the original price is $345.00, what is the laptop's current sale price?
A laptop computer is on sale for 40% less than the original price. If the original price is $345.00, what is the laptop's current sale price?
First, multiply the original price by the sale percentage:
Then, subtract that amount from the original price to get the sale price:
.
The laptop's current sale price is 
First, multiply the original price by the sale percentage:
Then, subtract that amount from the original price to get the sale price:
The laptop's current sale price is
Compare your answer with the correct one above
Helen wants to buy a dress for a party. It is on sale for 37% off. How much does the dress currently costs, if its original price was $45.00?
Helen wants to buy a dress for a party. It is on sale for 37% off. How much does the dress currently costs, if its original price was $45.00?
First, multiply 45 by 0.37:
Then, subtract that amount from 45.00 to find the sale price:
Answer: The dress' sale price is $28.35.
First, multiply 45 by 0.37:
Then, subtract that amount from 45.00 to find the sale price:
Answer: The dress' sale price is $28.35.
Compare your answer with the correct one above
A restaurant is having a sale and lowering their prices by 20%. If an average meal for two normally costs $62.00, what will it costs under the current sale?
A restaurant is having a sale and lowering their prices by 20%. If an average meal for two normally costs $62.00, what will it costs under the current sale?
Multiply: 
Then, subtract that amount from the original price:
Answer: $49.60
Multiply:
Then, subtract that amount from the original price:
Answer: $49.60
Compare your answer with the correct one above
A class with 
students went on a field trip, but one of the students was absent. What percentage of students in the class went on the field trip?
A class with
The percentage of students who attended the field trip can be found by dividing the number present by the total number of students. Here this is 
divided by 
. You then multiply by 
to get the percentage.
The percentage of students who attended the field trip can be found by dividing the number present by the total number of students. Here this is
Compare your answer with the correct one above
To get on the ballot for student body president, a student must turn in a petition with the signatures of 3% of the students. If there are 5,319 students, how many signatures must a student get to be on that ballot? (Nearest whole person)
To get on the ballot for student body president, a student must turn in a petition with the signatures of 3% of the students. If there are 5,319 students, how many signatures must a student get to be on that ballot? (Nearest whole person)
3% of 5,319 can be calculated by multiplying 5,319 by 0.03, the decimal equivalent of 3%:
Multiply 5,319 by 3, then move the decimal point so that two digits are to the right:
,
so
Rounded to the nearest whole number, this is 160 signatures.
3% of 5,319 can be calculated by multiplying 5,319 by 0.03, the decimal equivalent of 3%:
Multiply 5,319 by 3, then move the decimal point so that two digits are to the right:
so
Rounded to the nearest whole number, this is 160 signatures.
Compare your answer with the correct one above
To get on the ballot for student body president, a student must turn in a petition with the signatures of 4% of the students. If there are 3,268 students, how many signatures must a student get to be on that ballot? (Round to the nearest whole person.)
To get on the ballot for student body president, a student must turn in a petition with the signatures of 4% of the students. If there are 3,268 students, how many signatures must a student get to be on that ballot? (Round to the nearest whole person.)
4% of 3,268 can be calculated by multiplying 3,268 by 0.04, the decimal equivalent of 4%:
Multiply 3,268 by 4, then move the decimal point two places to the right:
,
so
Rounded to the nearest whole number - 131 signatures.
4% of 3,268 can be calculated by multiplying 3,268 by 0.04, the decimal equivalent of 4%:
Multiply 3,268 by 4, then move the decimal point two places to the right:
so
Rounded to the nearest whole number - 131 signatures.
Compare your answer with the correct one above
Refer to the above diagram. If there were 15,934 voters who were affiliated with a political party in Smith County in 2009, how many voters (nearest whole number) were there total?
Refer to the above diagram. If there were 15,934 voters who were affiliated with a political party in Smith County in 2009, how many voters (nearest whole number) were there total?
40% of the voters were registered as independents, so 60% were registered as a member of a political party. Since 60% of the voters numbered 15,934, we can find the total number of voters by setting up and solving a proportion:
which rounds to 26,557 voters.
40% of the voters were registered as independents, so 60% were registered as a member of a political party. Since 60% of the voters numbered 15,934, we can find the total number of voters by setting up and solving a proportion:
which rounds to 26,557 voters.
Compare your answer with the correct one above
Refer to the above graph. If there were 17,856 registered voters in Smith County in 2009, how many voters were registered as neither Republicans nor Democrats (nearest whole number)?
Refer to the above graph. If there were 17,856 registered voters in Smith County in 2009, how many voters were registered as neither Republicans nor Democrats (nearest whole number)?
2% of the voters were registered as members of other parties, and 40% were unaffiliated, so we want to calculate 42% of 17,856, or, equivalently,
which, to the nearest whole number, rounds to 7,500 voters.
2% of the voters were registered as members of other parties, and 40% were unaffiliated, so we want to calculate 42% of 17,856, or, equivalently,
which, to the nearest whole number, rounds to 7,500 voters.
Compare your answer with the correct one above
Candy bought a sweater and a beanie on sale for 20% off. If the sweater cost $
and the beanie cost $
, how much did Candy spend?
Candy bought a sweater and a beanie on sale for 20% off. If the sweater cost $
In order to find how much money Candy spent, we must first figure out the cost of the merchandise before the discount. We do this by adding the prices together.
Next we must find 20% of $57.00.
Since 20% is the percentage Candy saved, we must subtract $11.40 from the original price.
So Candy spent $45.60.
In order to find how much money Candy spent, we must first figure out the cost of the merchandise before the discount. We do this by adding the prices together.
Next we must find 20% of $57.00.
Since 20% is the percentage Candy saved, we must subtract $11.40 from the original price.
So Candy spent $45.60.
Compare your answer with the correct one above
What percent of 96 is 24?
What percent of 96 is 24?
Translate the sentence into an equation
Isolate 
and you get 
.
Remember that the question is asking for a percentage, so convert 
into 
.
Translate the sentence into an equation
Isolate
Remember that the question is asking for a percentage, so convert
Compare your answer with the correct one above