High School

If [tex]$f(3)=191.5$[/tex] when [tex]$r=0.03$[/tex] for the function [tex]$f(t)=P e^t$[/tex], then what is the approximate value of [tex]$P$[/tex]?



A. 210

B. 471

C. 175

D. 78

Answer :

We are given the function

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

with $r = 0.03$ and the condition $f(3) = 191.5$. Substituting $t=3$ and $r=0.03$ into the function, we get

$$
f(3) = P e^{0.03 \times 3} = P e^{0.09} = 191.5.
$$

To solve for $P$, divide both sides of the equation by $e^{0.09}$:

$$
P = \frac{191.5}{e^{0.09}}.
$$

Evaluating the denominator, we find that

$$
e^{0.09} \approx 1.09417.
$$

Thus, the value of $P$ is approximately

$$
P \approx \frac{191.5}{1.09417} \approx 175.
$$

Therefore, the approximate value of $P$ is $\boxed{175}$, which corresponds to option C.