# ACT Math : Decimals and Percentage

## Example Questions

### Example Question #121 : Arithmetic

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? Possible Answers:$10

$16$20

$30$24

$24 Explanation: 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 #122 : Arithmetic

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)

n(1-p)/100

np

n(100-p)

n(1-p)

Explanation:

The proportion of pennies before 1983 would be np. Therefore, the pennies dated 1983 or later would be n(1-p).

### Example Question #123 : Arithmetic

Express the following as a decimal:

Explanation:

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 #124 : Arithmetic

Which of the following is equivalent to  ?

Explanation:

To find a decimal from a percentage, divide the percentage value by . In this case, convert the fraction to a decimal first:

### Example Question #125 : Arithmetic

share in a stock is added to a  share by speculators. What is the decimal equivalent of the combined shares?

Explanation:

To convert from a percentage to a decimal, divide the decimal by . In this case, we can add the percentages first.

### Example Question #126 : Arithmetic

Sally sees a jacket on sale that's . The store is having a  storewide discount. What is the price of the jacket after the discount is applied?

Explanation:

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 isThe 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 .

### Example Question #1 : Decimals And Percentage

A high school senior takes a survey of the entire senior class for a project. She's interested in seeing the distribution of what her peers decide to pursue in college. She came up with the following data:

The rest of the  students stated an interest in Linguistics. How many students in total were surveyed?

Explanation:

In this question, information about 5 groups of students is included but isn't expressed in the table nor is it expressed in terms of a percentage.

The sample the student took, despite how many students were interviewed, will have all the percents add up to 100% - as in the case with any study with percent breakdowns. The number of prospective Linguistic students is given (37), and it's know they're a part of the 100% the sample provides. To determine their percent, all the other intended majors percents must be subtracted from the total (100%).

Once this information has been uncovered, this problem becomes a matter of being able to calculate what 37 is 6% ofThis can be uncovered through the use of . In this question, the percent and "is" is known. The goal is to find what the "of" is. The of will provide the total number of students surveyed. Denoting the "of" as x, substituting all information in, and undergoing cross multiplication will provide the final answer.

Given that fractions of a person cannot be surveyed, the final answer must be rounded to the nearest whole number.

### Example Question #1201 : Act Math

Which of the following is equivalent to ?

Explanation:

To convert a decimal into a percent is fairly straightforward. Begin with your original decimal value:

Then, move your decimal point to the right by two:

Strip off any leading zeroes, add a percent sign, and you are good to go!

### Example Question #1202 : Act Math

At high elevations, the ability of red blood cells to hold oxygen is decreased. At a particular elevation, the red blood cells' ability to hold oxygen is multiplied by . What percentage of the normal amount does this represent?

Explanation:

To find a percentage from a decimal, multiply the decimal by .

### Example Question #1203 : Act Math

A chemist mixes a solution out of a bottle which states   on the label with some pure water. What is the strength of the solution in the bottle, as a percentage?