Given that the supply function for the company is equal to the square of the price of their product, all divided by three,
i.e. [tex]Q_s=\frac{p^2}{3}[/tex]
and the demand is a basic 920 units minus thirty times price, minus a quarter of the square of the price,
i.e. [tex]Q_d=920-30p- \frac{1}{4} p^2[/tex]
The ideal price of their product, to make sure that there is neither a surplus nor a shortage is the equilibrium price which is the price when supply equals demand.
i.e.
[tex]Q_s=Q_d \\ \\ \Rightarrow\frac{p^2}{3}=920-30p- \frac{1}{4} p^2 \\ \\ \Rightarrow \frac{7}{12} p^2+30p-920=0 \\ \\ \Rightarrow p= \frac{-30\pm\sqrt{30^2-4(\frac{7}{12})(-920)}}{2(\frac{7}{12})} \\ \\ =\frac{-30\pm\sqrt{900+\frac{6440}{3}}}{\frac{7}{6}}=\frac{-30\pm\sqrt{\frac{9140}{3}}}{1.1667} \\ \\ =\frac{-30\pm55.1966}{1.1667}= \frac{25.1966}{1.1667} =21.60[/tex]
Therefore, the ideal price of their product, to make sure that there is neither a surplus nor a shortage is $21.60
The number of units they will sell at this price is given by
[tex]Q= \frac{(21.60)^2}{3} \\ \\ = \frac{466.43}{3} \approx155\ units[/tex]