College

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. 24
C. 225
D. 371

Answer :

We are given the function

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

with [tex]$r = 0.05$[/tex], and it is known that [tex]$f(5) = 288.9$[/tex]. To find [tex]$P$[/tex], we first substitute [tex]$t = 5$[/tex] and [tex]$r = 0.05$[/tex] into the function:

[tex]$$
f(5) = P e^{0.05 \cdot 5} = P e^{0.25}.
$$[/tex]

Since [tex]$f(5) = 288.9$[/tex], we have:

[tex]$$
288.9 = P e^{0.25}.
$$[/tex]

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

[tex]$$
P = \frac{288.9}{e^{0.25}}.
$$[/tex]

Using the approximation [tex]$e^{0.25} \approx 1.2840254166877414$[/tex], we find

[tex]$$
P \approx \frac{288.9}{1.2840254166877414} \approx 224.9955.
$$[/tex]

Rounding to the nearest whole number gives

[tex]$$
P \approx 225.
$$[/tex]

Thus, the approximate value of [tex]$P$[/tex] is [tex]$\boxed{225}$[/tex], which corresponds to option C.