Math Problem Statement

Biologists have found that the number of chirps some crickets make per minute is related to temperature. When crickets chirp 124 times per minute, it is about 68°F. When they chirp 172 times per minute, it is about 80°F. a) Find an equation for the line that models this situation. b) How warm is it when the crickets are chirping 150 times a minute?

Solution

Let's analyze the problem step by step.

1. Identifying Variables

  • xx: The number of chirps per minute.
  • yy: The temperature in degrees Fahrenheit.

2. Given Information

The problem gives two points:

  • When the crickets chirp 124 times per minute, the temperature is 68°F. This gives the point (124,68)(124, 68).
  • When the crickets chirp 172 times per minute, the temperature is 80°F. This gives the point (172,80)(172, 80).

3. Finding the Slope

The slope mm of the line can be found using the slope formula: m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1} Substituting the values of the two points (124,68)(124, 68) and (172,80)(172, 80): m=8068172124=1248=0.25m = \frac{80 - 68}{172 - 124} = \frac{12}{48} = 0.25

So, the slope m=0.25m = 0.25.

4. Finding the y-Intercept

Now, we can use the point-slope form of the equation of a line: yy1=m(xx1)y - y_1 = m(x - x_1) Using the point (124,68)(124, 68) and the slope m=0.25m = 0.25: y68=0.25(x124)y - 68 = 0.25(x - 124) Simplifying this: y68=0.25x31y - 68 = 0.25x - 31 y=0.25x31+68y = 0.25x - 31 + 68 y=0.25x+37y = 0.25x + 37 So, the equation of the line is: y=0.25x+37y = 0.25x + 37 This gives us the y-intercept of 3737.

5. Answering the Questions

  • The y-intercept is 37.
  • The slope is 0.25.

Part a: Equation

The equation for the line modeling the situation is: y=0.25x+37y = 0.25x + 37

Part b: Finding the Temperature When Chirping 150 Times per Minute

We can substitute x=150x = 150 into the equation: y=0.25(150)+37=37.5+37=74.5y = 0.25(150) + 37 = 37.5 + 37 = 74.5 So, when the crickets chirp 150 times per minute, the temperature is approximately 74.5°F.


Would you like any more details or explanations?

Related Questions:

  1. What does the slope of the line represent in the context of this problem?
  2. How would the equation change if the crickets chirped 200 times per minute at 90°F?
  3. How would you graph this equation and what would the graph look like?
  4. If the temperature was 85°F, how many chirps per minute would the crickets make?
  5. What is the significance of the y-intercept in this situation?

Tip:

The slope in linear relationships can often be interpreted as the rate of change between two variables—in this case, the rate at which the temperature changes per additional cricket chirp.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Slope-Intercept Form

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Slope-Intercept Equation: y = mx + b

Theorems

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Suitable Grade Level

Grades 8-10