Question

janelys 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 days high temperature and then draw the line of best fit. based on the line of best fit, how many hot cocoas would you predict janelys to sell if the days high temperature were 56°f?

Explanation:

Step1: Find the slope of the line of best - fit

The slope formula is $m=\frac{y_2 - y_1}{x_2 - x_1}$. Using two points on the line of best - fit, say $(0,90)$ and $(48,48)$. Then $m=\frac{48 - 90}{48-0}=\frac{- 42}{48}=-\frac{7}{8}=-0.875$.

Step2: Find the y - intercept

The y - intercept $b$ is the value of $y$ when $x = 0$. From the point $(0,90)$, $b = 90$.

Step3: Write the equation of the line

The equation of a line is $y=mx + b$. Substituting $m=-0.875$ and $b = 90$, we get $y=-0.875x + 90$.

Step4: Predict the number of hot cocoas

We want to find $y$ when $x = 56$. Substitute $x = 56$ into the equation $y=-0.875\times56+90$. First, $-0.875\times56=-49$. Then $y=-49 + 90=41$.

Answer:

41