A population is increasing according to the exponential function defined by $y = 3 \mathrm { e }$ - $04 \mathrm { x }$, where $\mathrm { y }$ is in millions and $x$ is the number of years. Which of the following should be done in order to answer the question "When will the population reach 4 million?"
A) Solve $3 e ^ { .04 x } = 12$.
B) Solve $3 e ^ { .04 x } = 4$.
C) Evaluate $\mathrm { y } = 3 \mathrm { e } ^ { - 04 ( 1 / 4 ) }$.
D) Evaluate y $= 3 e .04 ( 4 )$.

Question

Quizplus · Accepted Answer

To find when the population reaches 4 million, you need to set the given exponential function equal to 4 (since $y$ represents the population in millions) and solve for $x$. This corresponds to option B: $3e^{.04x} = 4$.

A Population Is Increasing According to the Exponential Function Defined y=3ey = 3 \mathrm { e }y=3e

A Population Is Increasing According to the Exponential Function Defined $y = 3 \mathrm { e }$