Answer
$480$ million phones
Work Step by Step
We expect a shortage, because ${{\$}} 80$ is below the equilibrium price (which we found in part (a)).
When p=80,
Demand:
$\quad\left[\begin{array}{l}
q=-10(80)+1600\\
q=800
\end{array}\right]\quad $
Supply:
$\left[\begin{array}{l}
q=14(80)-800\\
q=320
\end{array}\right]$
The demand is $800-320=480$ million phones greater than the supply. That is, there is a shortage of $480$ million phones.
