An exterminator estimated there were 12,000 termites in a house. Each time the house was sprayed, the number of termites was reduced to one-fourth the previous number. How many termites were there after the house was sprayed [tex]$x$[/tex] times? Write a function to represent this scenario.

A. [tex]$f(x) = 12,000 + \left(\frac{1}{4}\right)^x$[/tex]
B. [tex]$f(x) = 12,000\left(\frac{1}{4}\right)^x$[/tex]
C. [tex]$f(x) = \frac{1}{4}(12,000)^x$[/tex]
D. [tex]$f(x) = 12,000 - \left(\frac{1}{4}\right)^x$[/tex]



Answer :

Let's work through the problem and derive the correct function step-by-step.

First, consider the initial number of termites, which is 12,000.

When the house is sprayed once, the number of termites is reduced to one-fourth of the initial number. Therefore, after one spray, the number of termites would be:

[tex]\[ \text{Number of termites after 1 spray} = 12,000 \times \frac{1}{4} \][/tex]

When the house is sprayed a second time, the number of termites is again reduced to one-fourth of the number from the previous spray. So after two sprays, the number of termites would be:

[tex]\[ \text{Number of termites after 2 sprays} = 12,000 \times \left(\frac{1}{4}\right) \times \left(\frac{1}{4}\right) = 12,000 \times \left(\frac{1}{4}\right)^2 \][/tex]

Similarly, after three sprays, it would be reduced to:

[tex]\[ \text{Number of termites after 3 sprays} = 12,000 \times \left(\frac{1}{4}\right) \times \left(\frac{1}{4}\right) \times \left(\frac{1}{4}\right) = 12,000 \times \left(\frac{1}{4}\right)^3 \][/tex]

From this pattern, after [tex]\(x\)[/tex] sprays, the number of termites would be:

[tex]\[ \text{Number of termites after } x \text{ sprays} = 12,000 \times \left(\frac{1}{4}\right)^x \][/tex]

So the function [tex]\(f(x)\)[/tex] that represents the number of termites after [tex]\(x\)[/tex] sprays is:

[tex]\[ f(x) = 12,000 \left(\frac{1}{4}\right)^x \][/tex]

Comparing this to the given options, the correct answer is:

B. [tex]\(f(x) = 12,000\left(\frac{1}{4}\right)^x\)[/tex]