College

Using the equation [tex]y = 20000(0.95)^z[/tex], predict the purchasing power of [tex]\$20,000[/tex] ten years later.

A. [tex]\$10,255[/tex]
B. [tex]\$11,975[/tex]
C. [tex]\$12,635[/tex]
D. [tex]\$14,560[/tex]

Answer :

To predict the purchasing power of \[tex]$20,000 ten years later using the equation

$[/tex][tex]$
y = 20000(0.95)^z,
$[/tex][tex]$

we set the number of years $[/tex]z = 10[tex]$. This gives:

$[/tex][tex]$
y = 20000(0.95)^{10}.
$[/tex][tex]$

Step 1. Calculate the decay factor over 10 years:

Compute

$[/tex][tex]$
(0.95)^{10} \approx 0.59874.
$[/tex][tex]$

This means the purchasing power retains about 59.874% of its initial value after 10 years.

Step 2. Multiply by the initial amount:

Now, multiply this factor by \$[/tex]20,000:

[tex]$$
y = 20000 \times 0.59874 \approx 11974.74.
$$[/tex]

Step 3. Rounding:

Rounding \[tex]$11974.74 to the nearest dollar gives approximately \$[/tex]11,975.

Thus, the purchasing power of \[tex]$20,000 ten years later is about \$[/tex]11,975.