The concentration of pollutants in a stream is given by $y=.06 e^{-3 x}$, where $y$ is the amount of pollutant in grams per liter and $x$ is the distance, in kilometers, downstream from the source of the pollution. Match each question with one of the solutions A, B, C, or D.
-How far downstream is the pollutant level equal to $.02 \mathrm{gm} / \mathrm{L}$ ?
A) Solve $.02=.06 e^{-3 x}$
B) Solve $\frac{1}{2}(.06)=.06 e^{-3 x}$
C) Evaluate $.06 e^{-3(.02)}$
D) Evaluate $.06 e^{-3(1 / 2)}$

Question

Quizplus · Accepted Answer

To find the distance downstream where the pollutant level equals .02 gm/L, we need to solve the equation $.02 = .06 e^{-3x}$ for $x$, which directly matches option A.

The Concentration of Pollutants in a Stream Is Given By y=.06