Questions: Oylan has a part-time job at an ice skating rink selling hot cocoa. He decided to plot the number of hot cocoas he 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 Dylan to sell if the day's high temperature were 25°F?

Solution Steps

The line of best fit passes through the points (0, 104), (5, 100), and (10, 96). Using the points (0, 104) and (10, 96), the slope of the line is $$m = \frac{96 - 104}{10 - 0} = \frac{-8}{10} = -\frac{4}{5}$$ The y-intercept is 104, so the equation of the line of best fit is $$y = -\frac{4}{5}x + 104$$

We are given a temperature of 25°F, so we substitute $x = 25$ into the equation: $$y = -\frac{4}{5}(25) + 104$$ $$y = -4(5) + 104$$ $$y = -20 + 104$$ $$y = 84$$

Final Answer