Korina is filling a basket with oranges of equal weight. Draw a graph and write an equation to represent this situation.

The table shows the relationship between the number of oranges and the total weight of the basket. After 2 oranges, the total weight of the basket is 15 ounces. After 5 oranges, the total weight is 27 ounces. Plot the two points on the graph to show the total weight of the basket of oranges after 2 oranges and 5 oranges are put in the basket.
Number of oranges Total weight (oz)
2 15
5 27
Nice!
For each orange added to the basket, the total weight increases at a constant rate. So, we can draw a line through these two points to show the linear relationship between the number of oranges and the total weight in ounces. Let’s write an equation to represent this line in the form y=mx+b. Start by finding m, or the slope. What is the slope of this line?
x
y
(2, 15)(5, 27)
0
1
2
3
4
5
6
0
3
6
9
12
15
18
21
24
27
30
33
Number of oranges
Total weight (oz)
y= mx + b

Slope =

1 answer

To find the slope \(m\) of the line that represents the relationship between the number of oranges \(x\) and the total weight \(y\), we can use the formula for slope:

\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]

Using the points from the table:

  • \( (x_1, y_1) = (2, 15) \)
  • \( (x_2, y_2) = (5, 27) \)

Substituting in these values:

\[ m = \frac{27 - 15}{5 - 2} = \frac{12}{3} = 4 \]

The slope \(m = 4\) means that for each orange added to the basket, the total weight increases by 4 ounces.

Finding the y-intercept \(b\)

Now that we know \(m\), we can use one of the points to find the y-intercept \(b\) in the equation \(y = mx + b\). Let's use the point \( (2, 15) \):

\[ 15 = 4(2) + b \] \[ 15 = 8 + b \] \[ b = 15 - 8 = 7 \]

The equation

Now we can write the equation of the line:

\[ y = 4x + 7 \]

Graph

To illustrate this, we can graph the two points:

  • Point \( (2, 15) \)
  • Point \( (5, 27) \)

On the x-axis, label the number of oranges (0 to 6) and on the y-axis, label the total weight (0 to 33 ounces). Plot the points and draw a line through them:

  1. For \(2\) oranges, plot the point at \( (2, 15) \).
  2. For \(5\) oranges, plot the point at \( (5, 27) \).
  3. Draw a straight line through both points to represent the relationship.

The resulting graph would be a straight line with a positive slope, indicating that as the number of oranges increases, the total weight also increases linearly.