When a Certain Commodity Is Sold for P Dollars Per $D ( p ) = \frac { 30,000 } { p }$

True/False

When a certain commodity is sold for p dollars per unit, consumers will buy $D ( p ) = \frac { 30,000 } { p }$ units per month. It is estimated that t months from now, the price of the commodity will be $p ( t ) = 0.3 t ^ { 5 / 2 } + 5.4$ dollars per unit. The monthly demand will be decreasing 40 months from now.