SAT Math : Arithmetic
Study concepts, example questions & explanations for SAT Math
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Example Questions
Example Question #19 : How To Find Percentage
What percent of 
Let's set up a proportion to solve this problem.
We're looking for a percentage, 
Our answer is
Example Question #281 : Arithmetic
Jones Elementary School has seven eighth-grade teachers; each teacher has the number of boys and girls listed above.
What percent of the students in eighth-grade are boys? Choose the closest answer.
The number of boys adds up to
The number of girls adds up to
The total number of students is therefore 
The percent of the students that are boys is
making 48% the closest choice.
Example Question #112 : Percentage
What percent of 
We can set up a proportion to solve this problem. Remember that a percentage can be written as a fraction.
Now we can cross-multiply to find our percent.
Therefore, our answer is 
Example Question #115 : Percentage
Marisa and Ted are running for senior class president. 150 votes have been tallied so far; 88 for Marisa and 62 for Ted. If 250 students total are voting, how many more votes must Marisa win in order to defeat Ted and earn exactly 50% more votes than him?
For Marisa to earn 50% more votes than Ted, she will need to earn 1.5 times his amount of votes. If we call Ted's amount of votes x, and the total number of votes is 250, we can set up the equation:
If we combine like terms, we get:
And if we solve for x, we get:
This means that Ted will get 100 votes. Since there are 250 votes total, we can figure out that Marisa will end up with 150 votes.
The question asks "how many more votes must Marisa win in order to defeat Ted and earn exactly 50% more votes than him?" and tells us that Marisa already has 88 votes.
Example Question #281 : Arithmetic
What percent of 
This question involves the verbal cues "of" and "is." "Of" means to multiply and "is" means equal.
Thus the equation to solve becomes: 
Example Question #1 : How To Find The Amount Of Sales Tax
If there is a 10% sale on an item, and then 9% sales tax is applied to that after-sale price, then what is the total cost of the item including tax as a percentage of its pre-sale sticker price?
99%
81.9%
101%
98.1%
99.2%
98.1%
A 10% sale means that the post-sale price of the item is now 90%, or 0.9 of the original cost of the item. We then apply 9% sales tax by multiplying the 0.9 by 109%, or 1.09. 0.9 * 1.09 = .981, so the total cost of the item is 98.1% of the original pre-sale sticker price.
For percentage problems that do not deal with a specific starting number, it is always helpful to plug in 100 for the starting number. Here, we would then have a post-sale price of 90 dollars, and if we calculate the sales tax for the 90-dollar item it would be 90 * 0.09 = $8.10. THis gives us a total cost of 90 + 8.10 = $98.10, or 98.1% of the original 100-dollar price.
Example Question #1 : How To Find The Amount Of Sales Tax
Cynthia buys 2 shirts, each costing $35, a pair of pants for $40 and a belt for $18. At the register the total she owes is $138.24. What is the rate of sales tax in her state?
To find the amount of sales tax, take the difference in the total before and after tax 
Example Question #1 : How To Find The Amount Of Sales Tax
A certain state charges sales tax at a rate of 8.75% per dollar spent. John spends $127.50 total, including tax, on clothes. What was the total price of the clothing before tax was added?
Since we know the total price with tax, we simply need to work backwards to remove the tax from the total price and find the price of the clothing itself. This can be done as follows:
Clothing Price or C = Total price / 1 + tax rate
C = $127.50/(1 + 0.0875) = $117.24
Example Question #2 : How To Find The Amount Of Sales Tax
Jack is at the grocery store. He buys 
Jack's groceries are not taxed, so they cost 
We will add the two together
Example Question #3 : How To Find The Amount Of Sales Tax
Harry, on his first lunch date with Sally, decides to put the entire bill on his credit card. If the bill came to $28 and Harry wants to leave an 18% tip, what is the total amount that he should pay?
To find an 18% increase, multiply by 1.18.
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