ACT Math : Arithmetic
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Example Questions
Example Question #1 : How To Find The Whole From The Part With Percentage
If 
Since 
Example Question #1 : How To Find The Whole From The Part With Percentage
Gwen has a collection of 1,000 books. The average thickness of each book is 1.25” thick. She wants to buy enough bookshelves that all of her books will fit on it.
What is the shortest length of bookshelf she should buy, in whole feet, to fit all her books?
105 feet
125 feet
115 feet
120 feet
110 feet
105 feet
Length of books = 1,000 books x 1.25” per book = 1,250”
Translate to feet
1” = 12’
1250” / 12 = 104.16 feet
Round up to 105 feet to be able to fit all the books.
Example Question #8 : How To Find The Whole From The Part With Percentage
Nathan spends 
If 
Solve for 
Example Question #1 : How To Find The Whole From The Part With Percentage
A bowl contains 
Which of the following expressions represents the total number of red marbles in the bowl?
It’s best to start with a fraction that is a part over 100. For this problem, we are looking for a fraction that shows 
If there are 4 marbles in the bowl, you’d expect 1 to be red. If we use this equation, we get
Example Question #31 : Percentage
Students at a country fair typically spend $40. The students have agreed to spend 40% less at this year's fair. Assuming all the students follow their new agreement, what is the most that could be spent by a student at this year's fair?
$24
$30
$16
$20
$10
$24
This is a percentage problem, so it is important to know that 40% of some value is equal to 0.4 of said value. So to find 40% of $40, we multiply 40 * 0.40, which equals 16. This 16 represents 40% of the original value of $40. So if a student was to spend 40% less than they usually spend, we would subtract $16, which is 40% of the original value, from $40, giving us an answer of $24.
Example Question #1 : Decimals And Percentage
There are n pennies in a jar. Let p represent the decimal ratio of the pennies that are dated before 1983. Which of the following equations repesents the number of pennies that are dated 1983 or later?
n(1-p)/100
np
n(1-p)
n(100-p)
n(1-p)
The proportion of pennies before 1983 would be np. Therefore, the pennies dated 1983 or later would be n(1-p).
Example Question #2 : Decimals And Percentage
Express the following as a decimal:
To convert a percentage to a decimal, you must add a decimal two points to the left from the right hand side. Thus,
Example Question #1 : Decimals And Percentage
Which of the following is equivalent to 
To find a decimal from a percentage, divide the percentage value by 
Example Question #5 : How To Find Decimal Equivalent To A Percentage
A 
To convert from a percentage to a decimal, divide the decimal by 
Example Question #121 : Arithmetic
Sally sees a jacket on sale that's 
The original price of the jacket is $53 and there's a discount applied that's close to being 50% off. Therefore we know the right answer should be a little greater than $26.50. This allows for the elimination of $24, $23.85 and $8.63 as options for viable answers.
This problem requires transitioning percentages into decimals as currency. In this case, it's helpful to keep in mind 
Using the information given, this skeleton would look like 
The intention of this is to see what 45% of $53.00 is. The is is what is being found, so it can be labeled as x. Using cross multiplication, x is calculated to be $23.85. X is what 45% of $53 is. Now the final calculation can be calculated through subtracting the x value from the jacket's original price 
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