Math Problem Statement

Kennedy has a part-time job at an ice skating rink selling hot cocoa. She decided to plot the number of hot cocoas she sold relative to the day's high temperature and then draw the line of best fit. Based on the line of best fit, how many hot cocoas would you predict Kennedy to sell if the day’s high temperature were 40°F?

Solution

The problem asks us to predict the number of hot cocoas Kennedy would sell when the day's high temperature is 40°F, based on the line of best fit shown in the graph.

From the image:

  1. The line of best fit passes through points such as (0, 84), (8, 77), and (24, 63). We can use these points to calculate the slope mm and the equation of the line.

To find the slope mm between two points, say (0, 84) and (24, 63): m=6384240=2124=0.875m = \frac{63 - 84}{24 - 0} = \frac{-21}{24} = -0.875

Next, we use the slope-intercept form y=mx+by = mx + b, where bb is the y-intercept (which is 84 because the line passes through (0, 84)).

Thus, the equation of the line is: y=0.875x+84y = -0.875x + 84

Now, substitute x=40x = 40 into the equation to predict the number of hot cocoas sold at 40°F: y=0.875(40)+84=35+84=49y = -0.875(40) + 84 = -35 + 84 = 49

So, Kennedy would sell 49 hot cocoas if the temperature were 40°F.

Would you like more details on how the equation of the line was derived, or do you have any questions? Here are 5 related questions you might explore:

  1. How would the equation change if the slope were steeper?
  2. What does the y-intercept represent in this context?
  3. How can you predict the number of hot cocoas sold at a different temperature, like 50°F?
  4. If the line of best fit changes, how would that impact the predictions?
  5. What happens if there’s a significant outlier in the data points?

Tip: Always check the graph's axis labels and units when solving prediction problems based on visual data!

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Slope-Intercept Form

Formulas

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

Theorems

Linear Relationships
Best Fit Line

Suitable Grade Level

Grades 8-10