a) Since we are interested in the number of TVs that can be sold at $400, we need to use the Demand model equation and set p=400; thus,
[tex]\begin{gathered} p=400 \\ \Rightarrow N=-7\cdot400+2820=20 \\ \Rightarrow N=20 \end{gathered}[/tex]
The answer to part a) is 20 TVs per week.
b) Set N=N, then
[tex]\begin{gathered} N=N \\ \Rightarrow-7p+2820=2.4p \\ \Rightarrow9.4p=2820 \\ \Rightarrow p=\frac{2820}{9.4}=300 \\ \Rightarrow p=300 \end{gathered}[/tex]
Therefore, using p=300 and solving for N,
[tex]\begin{gathered} \Rightarrow N=2.4\cdot300=720 \\ \Rightarrow N=720 \end{gathered}[/tex]
The answer to part b) is 720 TVs per week.
c) In part b), we found that when supply and demand are equal, p=300. Thus, the answer to part c) is $300
