ANSWER
$28
EXPLANATION
The profit function is given as:
[tex]p(x) = - 2 {(x - 9)}^{2} + 100[/tex]
where x is the price of the T-shirt in dollars.
To find the profit on a T-shirt whose price is $15, we substitute x=15 into the function and simplify.
[tex]p(15) = - 2 {(15 - 9)}^{2} + 100[/tex]
We simplify to get:
[tex]p(15) = - 2 {(6)}^{2} + 100[/tex]
[tex]p(15) = -72+ 100[/tex]
[tex]p(15) = 28[/tex]