SAT Math : Whole and Part
Study concepts, example questions & explanations for SAT Math
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Example Questions
Example Question #33 : Percentage
An artist's new album sold 
Let's set up a proportion to solve this problem, where 
Now, we can solve for the unknown by cross-multiplying.
Example Question #11 : Whole And Part
Jane called one thousand times to tell you she's sorry. If you saw she was calling and let your phone go to voicemail 
None of the given answers
To solve this problem, we can set up a proportion. Remember we can express percentages as fractions. Let 
Now, we can cross-multiply and solve for the unknown.
Example Question #11 : Whole And Part
Cannot be determined
To solve this we need to set up a proportion.
Now we cross multiply
Divide by 180.
Example Question #71 : Percentage
David's trip expenses are pictured in the above pie chart (numbers = % of his total expenses). If he spent $75 on taxis, how much did he spend on hotel and souvenirs combined?
$200
$225
$40
$250
$175
$200
David spent $75 on taxis, which were 15% of his total expenses on the trip. He therefore spent 75(100/15) = $500 on the trip altogether. The hotel and souvenirs make up 35% + 5% = 40% of his total expenses. 40% of 500 is $200.
Example Question #72 : Percentage
30% of what number is 20?
Solve to the nearest hundredth.
1.5
None of the other answers
66.67
0.67
150%
66.67
This is a very basic form percentage question. This can be rewritten:
0.3 * x = 20
(Remember, the word "of" in a word problem indicates multiplication, while the word "is" indicates an equals sign).
Solve for x: x = 20 / 0.3 = 66.67
Example Question #1 : Whole And Part
A toy is on sale for 43% off. Its sale price is $21.37. What is the full price?
None of the available answers
An algebraic expression for this item is:
Example Question #2 : Whole And Part
Twenty-six students planned to contribute an equal amount to purchase a gift for their teacher. After 18 students had paid, they had collected $76.50. What is the total price of the gift?
If $76.50 had been collected after 18 students had paid, we can determine how much each student contributed:
$76.50/18 = $4.25 per student
Now we can multiply this by the total number of students (26) to get the full price of the gift:
26 x $4.25 = $110.50
Example Question #1 : Whole And Part
If 
20
100
50
10
200
50
The first part of the problem tells us that x% of 20 is 50. We can model x% as x/100 or 0.01x. To find x% of 20, we can multiply 0.01x and 20. In other words, we can write the following equation:
(0.01x)(20) = 50
Divide both sides by 20.
0.01x = 2.5
Divide both sides by 0.01.
x = 250.
The question then asks us to find 20% of x. We can represent 20% as 0.2, and we know that x is 250. Therefore,
20% of 250 = 0.2(250) = 50.
The answer is 50.
Example Question #3 : Whole And Part
If 
Let x be the number in question.
Then 2/3 * x = 18.
x = 18 * 3/2 = 27
Now find 1/9 of 27:
1/9 * 27 = 3
Example Question #2 : How To Find The Whole From The Part With Percentage
17 is 85% of what number?
In this case, 17 is part of a whole x. We are also given that 17 is 85% of x.
With this in mind, we can set up the following proportion.
To solve for x, cross multiply.
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