High School

If [tex]f(5)=288.9[/tex] when [tex]r=0.05[/tex] for the function [tex]f(t)=P e^{rt}[/tex], then what is the approximate value of [tex]P[/tex]?

A. 3520
B. 371
C. 24
D. 225

Answer :

We are given the function

$$
f(t) = P e^{rt}
$$

with $r = 0.05$ and $f(5) = 288.9$. This means that when $t = 5$, the equation becomes

$$
P e^{0.05 \times 5} = 288.9.
$$

Simplify the exponent:

$$
0.05 \times 5 = 0.25,
$$

so we have

$$
P e^{0.25} = 288.9.
$$

To solve for $P$, divide both sides of the equation by $e^{0.25}$:

$$
P = \frac{288.9}{e^{0.25}}.
$$

Evaluating $e^{0.25}$ gives approximately $1.2840254166877414$. Therefore,

$$
P \approx \frac{288.9}{1.2840254166877414} \approx 224.99554622932885.
$$

Rounding this to the nearest whole number yields $225$.

Thus, the approximate value of $P$ is $\boxed{225}$.