Question

A music store sells regular CDs for $8.50. On average, the store sells 90 CDs every day. For each 50-cent increase in the price of regular CDs, the sales of CDs will go down by 5. What should the CD price be to get the most income from CD sales?

Answer 1

if the price is $8.50

$\begin{gathered} 8.50\times90 \\ =765 \end{gathered}$

if the priece is 9

$\begin{gathered} 9\times85 \\ =765 \end{gathered}$

if the priece is 10

$\begin{gathered} 10\times75 \\ =750 \end{gathered}$

if we increase the price of the CD the earnings decrease

if the priece is 8

$\begin{gathered} 8\times95 \\ =760 \end{gathered}$

if we decrease the price of the CD the earnings also decrease

the best prices are $8.50 and $9 because produce the same money