1. Michelle rents a movie for a flat fee of [tex]$\$[/tex]1.50[tex]$ plus an additional $[/tex]\[tex]$1.25$[/tex] for each night she keeps the movie. Choose the cost function that represents this scenario if [tex]\( x \)[/tex] equals the number of nights Michelle has the movie.

A. [tex]\( c(x) = 1.50 + 1.25x \)[/tex]
B. [tex]\( c(x) = 1.50x + 1.25 \)[/tex]
C. [tex]\( c(x) = 275 \)[/tex]
D. [tex]\( c(x) = (1.50 + 1.25)x \)[/tex]



Answer :

Let's break down the problem step-by-step to understand how the cost function is formulated based on the scenario provided.

1. Identify the flat fee and nightly charge:
- Flat fee: Michelle pays a flat fee of [tex]$1.50 to rent a movie. - Nightly charge: Additionally, she pays $[/tex]1.25 for each night she keeps the movie.

2. Define the variable:
- Let [tex]\( x \)[/tex] be the number of nights Michelle keeps the movie.

3. Formulate the cost function:
- The total cost [tex]\( c(x) \)[/tex] has two components:
- The flat fee of [tex]$1.50, which is constant regardless of the number of nights. - An additional charge of $[/tex]1.25 per night, which changes proportionally with the number of nights [tex]\( x \)[/tex].

4. Combine the components into one function:
- The flat fee component remains as [tex]$1.50. - The nightly charge component is $[/tex]1.25 times the number of nights [tex]\( x \)[/tex], which can be written as [tex]\( 1.25x \)[/tex].

5. Summing these components:
- The total cost function [tex]\( c(x) \)[/tex] is the sum of the flat fee and the nightly charges:
[tex]\[ c(x) = 1.50 + 1.25x \][/tex]

Upon examining the given choices, the correct choice of the cost function that represents this scenario is:
[tex]\[ c(x) = 1.50 + 1.25x \][/tex]

Thus, the correct answer is:
[tex]$ c(x) = 1.50 + 1.25x $[/tex]

This function correctly encapsulates the flat rental fee and the additional nightly charges specified in the problem.