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. 78
B. 175
C. 210
D. 471

Answer :

We are given the exponential function

[tex]$$
f(t) = P e^{rt},
$$[/tex]

with [tex]$f(3) = 191.5$[/tex], [tex]$r = 0.03$[/tex], and [tex]$t = 3$[/tex]. Substituting these values into the function, we have

[tex]$$
191.5 = P e^{0.03 \cdot 3}.
$$[/tex]

Since [tex]$0.03 \cdot 3 = 0.09$[/tex], the equation becomes

[tex]$$
191.5 = P e^{0.09}.
$$[/tex]

To solve for [tex]$P$[/tex], we isolate it by dividing both sides by [tex]$e^{0.09}$[/tex]:

[tex]$$
P = \frac{191.5}{e^{0.09}}.
$$[/tex]

Evaluating the exponential term, we find that [tex]$e^{0.09} \approx 1.094174$[/tex]. Hence,

[tex]$$
P \approx \frac{191.5}{1.094174} \approx 175.
$$[/tex]

Thus, the approximate value of [tex]$P$[/tex] is [tex]$\boxed{175}$[/tex], which corresponds to option B.