Question

Difficulty: MediumInterpreting Linear Relationships in Context

A commercial coffee roaster heats a large batch of coffee beans. The temperature TT, in degrees Celsius (C^\circ\text{C}), of the beans mm minutes after heating begins is modeled by the equation T=18m+31T = 18m + 31, where m10m \le 10. Which of the following is the best interpretation of 1818 in this context?

  1. The increase in the temperature of the beans, in degrees Celsius, for each minute of heating.Answer
  2. B
    The initial temperature of the beans, in degrees Celsius, when heating begins.
  3. C
    The number of minutes it takes for the temperature of the beans to increase by 1C1^\circ\text{C}.
  4. D
    The temperature of the beans, in degrees Celsius, after 1818 minutes of heating.

Answer

The increase in the temperature of the beans, in degrees Celsius, for each minute of heating.
The equation is in the slope-intercept form T=18m+31T = 18m + 31, where 1818 is the slope and 3131 is the y-intercept. In this context, TT represents the temperature of the beans and mm represents the time in minutes. The slope, 1818, represents the rate of change of the temperature with respect to time, which means the temperature increases by 18C18^\circ\text{C} for each minute of heating.

Step-by-Step Solution

1
Identify the component of the linear equation being questioned.
The number 1818 is the coefficient of the variable mm in the linear equation T=18m+31T = 18m + 31.
We need to determine what role the coefficient of the independent variable plays in a linear model.
2
Determine the mathematical meaning of the coefficient in a linear equation of the form y=mx+by = mx + b.
The coefficient of mm, which is 1818, represents the slope or the rate of change of TT with respect to mm.
In a linear function, the slope represents the change in the dependent variable per unit change in the independent variable.
3
Interpret the rate of change in the context of the problem.
Since TT is the temperature in degrees Celsius (C^\circ\text{C}) and mm is the time in minutes, a rate of change of 1818 means that the temperature increases by 18C18^\circ\text{C} for every 11 minute of heating.
This matches the definition of the slope in the given context.

Key Concept

Interpreting the slope of a linear relationship in context
Estimated Time:1m 0s
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