Answer:
40 more paintings in order to maximize sales making a total of 60 paintings
Step-by-step explanation:
Let x= no.of copies above 20
Total Sales(x) = (number of copies)(price per copy)
Sales (x)= (20 +x)(100 –x)
Open bracket
=1200-20x+100x-x^2
=1200+80x-x^2
Derivative of the sales
80-2x=0
80=2x
Divide both sides by 2
40=x
Because Sales(x)= –2, this is maximal by the second derivative test
The artist should make 40 more paintings in order to maximize sales making a total of 60 paintings.