A) For the first question, we will use the first and second derivative criteria. First, we will compute the first and second derivatives of the given function:
[tex]\begin{gathered} \frac{dP(q)}{dq}=2(-0.02)q+3 \\ \frac{d^{2}P(q)}{dq^{2}}=2(-0.02)=-0.04 \end{gathered}[/tex]
Now, we set the first derivative equals to zero and solve for q:
[tex]\begin{gathered} -0.04q+3=0 \\ q=\frac{-3}{-0.04}=75 \end{gathered}[/tex]
Evaluating q=75 in the second derivative, we get a negative value since it is a constant, therefore there is a maximum for q=75.
B) We know the maximum is reached for q=75 therefore to find the maximum profit we evaluate the function at q=75:
[tex]P(75)=-0.02(75)^{2}+3(75)-44=68.5[/tex]