Question 1091312
P(X)=-15x^2+ 600x+ 60 
The vertex has the x value = -b/2a=-600/-30 or 20
so x=$20, which is the maximum
the profit would be $6060.
{{{graph(300,300,-30,30,-400,10000,-15x^2+600x+60)}}}
at $21, the profit is $6045
at $19, the profit is $6045