To find the rate of change in the purchase price of broccoli per pound, we can use the formula for the slope \( m \) of a linear graph, which is given by:
\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]
Here, \( (x_1, y_1) = (3, 8.25) \) and \( (x_2, y_2) = (6, 16.50) \).
Now, we can plug in the values:
\[ m = \frac{16.50 - 8.25}{6 - 3} \]
Calculating the differences:
- \( y_2 - y_1 = 16.50 - 8.25 = 8.25 \)
- \( x_2 - x_1 = 6 - 3 = 3 \)
Now substitute these into the formula:
\[ m = \frac{8.25}{3} \]
Calculating this gives:
\[ m = 2.75 \]
Thus, the rate of change in the purchase price of broccoli is $2.75 per pound.