Answer:
[tex]\large \boxed{\sf \ \ \text{The maximum profit is \$94 per day.} \ \ }[/tex]
Step-by-step explanation:
Hello,
The coefficient in [tex]x^2[/tex] is negative.
So, there is a maximum at the vertex point which is
[tex]x=-\dfrac{b}{2a}==\dfrac{-6}{-0.2}=\dfrac{6}{0.2}=30[/tex]
And then the maximum is f(30)=
[tex]-0.1\cdot 30^2+6\cdot 30 +4=-90 +180+4=94[/tex]
So the maximum profit is 94 $ per day.
Hope this helps.
Do not hesitate if you need further explanation.
Thank you