Raffle tickets are being sold for a fundraiser. The relationship between [tex]\( n \)[/tex], the number of raffle tickets sold, and [tex]\( A \)[/tex], the amount of money in dollars raised, is given by the function below.

[tex]\[ A(n) = 3n - 20 \][/tex]

What is the equation of the inverse function [tex]\( N(a) \)[/tex]?

A. [tex]\( N(a) = \frac{a}{3} - 20 \)[/tex]

B. [tex]\( N(a) = \frac{a}{3} + 20 \)[/tex]

C. [tex]\( N(a) = \frac{a + 20}{3} \)[/tex]

D. [tex]\( N(a) = \frac{a - 20}{3} \)[/tex]



Answer :

To find the inverse function [tex]\( N(a) \)[/tex] of the function [tex]\( A(n) = 3n - 20 \)[/tex], we need to express [tex]\( n \)[/tex] in terms of [tex]\( a \)[/tex].

Here are the steps we will take:

1. Start with the original function:
[tex]\[ A(n) = 3n - 20 \][/tex]

2. Replace [tex]\( A(n) \)[/tex] with [tex]\( a \)[/tex]: This is the first step in finding the inverse. By setting [tex]\( A(n) = a \)[/tex], we get:
[tex]\[ a = 3n - 20 \][/tex]

3. Solve for [tex]\( n \)[/tex]: We need to isolate [tex]\( n \)[/tex]. To do this, first add 20 to both sides of the equation:
[tex]\[ a + 20 = 3n \][/tex]

4. Divide both sides by 3: To completely isolate [tex]\( n \)[/tex], divide both sides of the equation by 3:
[tex]\[ n = \frac{a + 20}{3} \][/tex]

So the inverse function [tex]\( N(a) \)[/tex] is:
[tex]\[ N(a) = \frac{a + 20}{3} \][/tex]

Considering the provided options, the correct answer is:
C. [tex]\( N(a) = \frac{a + 20}{3} \)[/tex]