The concentration CCC, in mg L−1\text{mg L}^{-1}mg L−1, of a certain chemical in a reaction is modeled by the equation C=12.5e−0.8tC = 12.5 e^{-0.8t}C=12.5e−0.8t, where ttt is the time in hours after the start of the reaction. Determine the rate of change of the concentration, in mg L−1h−1\text{mg L}^{-1}\text{h}^{-1}mg L−1h−1, at the instant when the concentration is exactly 2.4 mg L−12.4 \text{ mg L}^{-1}2.4 mg L−1.
