As a result of increasing energy costs, the growth rate of the profit of the 4-year old Venice Glassblowing Company has begun to decline. Venice's management, after consulting with energy experts, decides to implement certain energy-conservation measures aimed at cutting energy bills. The general manager reports that, according to his calculations, the growth rate of Venice's profit should be on the increase again within 4 years. If Venice's profit (in hundreds of dollars) $t$ years from now is given by the function $$P(t)=t^{3}-9 t^{2}+40 t+50 \quad(0 \leq t \leq 8)$$determine whether the general manager's forecast will be accurate.
Hint: Find the inflection point of the graph of $P$ and study the concavity of the graph of $P$.