Which phrase describes an unknown or changeable quantity?
A 80 miles per hour
B. 4 quarts in a gallon
C. The number of different colors en the page
D. A score of 27 points
The correct answer and explanation is :
The correct answer is:
C. The number of different colors on the page
Explanation (300+ words):
In mathematics and real-world contexts, an unknown or changeable quantity refers to something that is not fixed—it may vary or be undetermined at a given time. This type of quantity is often represented by a variable in math, such as x, y, or n. Let’s evaluate each answer choice to determine which best fits the definition of an unknown or changeable quantity.
Option A: “80 miles per hour”
This is a specific and fixed rate of speed. It represents a constant value and is not changeable in this context. Therefore, this is not an unknown or variable quantity.
Option B: “4 quarts in a gallon”
This is a mathematical conversion or unit equivalence. It is a well-established fact that does not change, so it is not a variable or unknown quantity. It is fixed and known.
Option C: “The number of different colors on the page”
This is the correct answer because the number of colors can vary from page to page. It is unknown until you look at the specific page and count them. For example, one page might have three colors while another might have seven. Since this number changes depending on the page, it represents a changeable quantity and could be modeled using a variable in an equation or expression.
Option D: “A score of 27 points”
This is a specific, known value. Once the score is 27, it is fixed and unchanging in that context. It is not variable, and there is no uncertainty about it.
Conclusion:
Only Option C refers to a quantity that is not known in advance and can change depending on the circumstances. In math, this is the type of value that would typically be represented by a variable.