Answer:
The selling price of phone that will give them the maximum revenue (in dollars) = 4 dollars
The amount of the maximum revenue (in dollars) = 16 dollars
Explanation:
Total number of phone sold = 8-X
Total price of each phone is X dollars
Total price of all sold mobile phones is
X * (8-X) = X^2 -8X
For getting maximum revenue, we will differentiate the above equation -
d/dx(X^2 -8X)= 0
2X -8 = 0
X = 4 dollars
Maximum revenue
4 * (8-4) = 16 dollars