Math Problem Statement

A lake near the Arctic Circle is covered by a [2]-meter-thick sheet of ice during the cold winter months. When spring arrives, the warm air gradually melts the ice, causing its thickness to decrease at a constant rate. After [3] weeks, the sheet is only [1.25] meters thick. Let [y] represent the ice sheet's thickness (in meters) after [x] weeks. Which of the following information about the graph of the relationship is given? Choose 1 answer: Choose 1 answer: (Choice A) Slope and [x]-intercept A Slope and [x]-intercept (Choice B) Slope and [y]-intercept B Slope and [y]-intercept (Choice C) Slope and a point that is not an intercept C Slope and a point that is not an intercept (Choice D) [x]-intercept and [y]-intercept D [x]-intercept and [y]-intercept (Choice E) [y]-intercept and a point that is not an intercept E [y]-intercept and a point that is not an intercept (Choice F) Two points that are not intercepts F Two points that are not intercepts

Solution

To determine the correct answer, we will analyze the problem step by step.

Given:

  1. The ice sheet starts with a thickness of 2 meters at the beginning (week 0).
  2. After 3 weeks, the thickness is reduced to 1.25 meters.
  3. We are tasked with identifying what specific information about the graph of this relationship is provided.

Step 1: Recognizing the linear relationship

The ice thickness decreases at a constant rate, which indicates that this is a linear relationship. In general, a linear relationship can be written in the form:

y=mx+by = mx + b

  • yy represents the ice thickness (in meters).
  • xx represents the time in weeks.
  • mm is the slope of the line (rate of change of thickness).
  • bb is the yy-intercept (initial thickness at x=0x = 0).

Step 2: Interpreting the information provided

From the problem:

  1. At x=0x = 0, the ice thickness y=2y = 2.

    • This gives the yy-intercept b=2b = 2.
  2. At x=3x = 3, the ice thickness y=1.25y = 1.25.

    • This gives a point (3,1.25)(3, 1.25) on the graph that is not an intercept.
  3. The slope mm (rate of change) can be calculated as:

m=change in ychange in x=1.25230=0.753=0.25m = \frac{\text{change in } y}{\text{change in } x} = \frac{1.25 - 2}{3 - 0} = \frac{-0.75}{3} = -0.25

Thus, the slope of the line is 0.25-0.25.


Step 3: Identifying the answer

From the above steps, we know:

  • The slope m=0.25m = -0.25 is provided.
  • The yy-intercept b=2b = 2 is also provided.
  • A point on the graph (3,1.25)(3, 1.25), which is not an intercept, is mentioned.

Since the yy-intercept and a point (that is not an intercept) are part of the information provided, the correct answer is:

Choice E: yy-intercept and a point that is not an intercept


Do you want me to clarify any part of this solution? Let me know!


Related Questions:

  1. How do you calculate the xx-intercept of this graph?
  2. What does the slope of 0.25-0.25 mean in the context of the problem?
  3. How long will it take for the ice to completely melt (thickness = 0)?
  4. Write the equation of the line that models the relationship between xx and yy.
  5. What would the graph of this relationship look like?

Tip:

When analyzing linear relationships, always identify the slope and intercepts first, as they provide critical information about the graph's behavior.

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Math Problem Analysis

Mathematical Concepts

Linear Relationships
Slope and Intercepts
Graphing Linear Equations

Formulas

y = mx + b

Theorems

Slope Formula
Interpretation of Linear Equations

Suitable Grade Level

Grades 7-9