High School

Question 1 of 10: Exponential Growth

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

A. 471
B. 175
C. 210
D. 78

Answer :

To find the approximate value of [tex]\( P \)[/tex] in the given exponential function [tex]\( f(i) = P \times e^{-r \times i} \)[/tex], we are provided with some values:

- [tex]\( f(3) = 191.5 \)[/tex]
- [tex]\( r = 0.03 \)[/tex]
- [tex]\( i = 3 \)[/tex]

The function can be expressed as:

[tex]\[ f(i) = P \times e^{-r \times i} \][/tex]

We need to find [tex]\( P \)[/tex] when [tex]\( f(3) = 191.5 \)[/tex]. This requires us to rearrange the equation to solve for [tex]\( P \)[/tex].

1. Start with the equation given:
[tex]\[ f(3) = P \times e^{-0.03 \times 3} \][/tex]

2. Substitute the known value of [tex]\( f(3) \)[/tex]:
[tex]\[ 191.5 = P \times e^{-0.09} \][/tex]

3. Calculate the value of [tex]\( e^{-0.09} \)[/tex]. Using a calculator, [tex]\( e^{-0.09} \approx 0.9139 \)[/tex].

4. Substitute this back into the equation:
[tex]\[ 191.5 = P \times 0.9139 \][/tex]

5. Now, solve for [tex]\( P \)[/tex] by dividing both sides by 0.9139:
[tex]\[ P = \frac{191.5}{0.9139} \][/tex]

6. Performing the division gives:
[tex]\[ P \approx 209.53 \][/tex]

Therefore, the approximate value of [tex]\( P \)[/tex] is closest to option C, which is 210.