interval(s) where the function is increasing and the interval(s) where it is decreasing.\f92. Drug Concentration in the Blood The concentration (in milligrams per cubic centimeter) of a certain drug in a patient's body t hr after injection is given by C (t) = 2+3 + 1 (0 0) If the barometric pressure as measured by a hot-air balloonist is 20 in. of mercury, what is the balloonist's72. Sales of a Product The total number of units of a new product sold t months after its introduction is given by N(t) = 20,000(1 - e-0.05t ) 2 (0