Answer:
[tex]P(n)=-2n+75[/tex]
Step-by-step explanation:
Let n represent the number of shirts in thousands and P represent the charge per shirt. n is the independent variable and P is the dependent variable.
Since 3000 shirts sell for $69 each, this can be represented as (3, 69). Also 7000 shirts sell for $61 each, this can be represented as (7, 61).
The equation showing the relationship is gotten using:
[tex]P-P_1=\frac{P_2-P_1}{n_2-n_1}(n-n_1) \\\\P-69=\frac{61-69}{7-3} (n-3)\\\\P=-2(n-3)+69\\\\P=-2n+75\\\\P(n)=-2n+75[/tex]