A store offers packing and mailing services to customers. The cost of shipping a box is a combination of a flat packing fee of [tex]$5 and an amount based on the weight in pounds of the box, $[/tex]2.25 per pound.

Which equation represents the shipping cost as a function of [tex]\( x \)[/tex], the weight in pounds?

A. [tex]\( f(x) = 2.25x + 5 \)[/tex]

B. [tex]\( f(x) = 5x + 2.25 \)[/tex]

C. [tex]\( f(x) = 2.25x - 5 \)[/tex]

D. [tex]\( f(x) = 5x - 2.25 \)[/tex]



Answer :

To solve this problem, we need to derive an equation that accurately represents the shipping cost as a function of [tex]$x$[/tex], where [tex]$x$[/tex] is the weight of the box in pounds.

### Step-by-Step Solution:

1. Understand the Components of Cost:
- There is a flat packing fee of [tex]$5 which does not change regardless of the weight of the box. - There is an additional charge of $[/tex]2.25 for every pound that the box weighs.

2. Express the Total Cost:
- The total cost for shipping a box will be the sum of the flat packing fee and the weight-dependent fee.

3. Form the Equation:
- Let [tex]$x$[/tex] represent the weight of the box in pounds.
- The cost due to the weight alone would be [tex]$2.25 \times x$[/tex].
- Adding the flat packing fee of [tex]$5, the total shipping cost can be represented as: \[ f(x) = 2.25x + 5 \] 4. Compare with the Given Options: - Option 1: \( f(x) = 2.25x + 5 \) - Option 2: \( f(x) = 5x + 2.25 \) - Option 3: \( f(x) = 2.25x - 5 \) - Option 4: \( f(x) = 5x - 2.25 \) 5. Determine the Correct Equation: - The flat fee is added to the per-pound cost, which matches Option 1: \( f(x) = 2.25x + 5 \). Therefore, the equation that correctly represents the shipping cost as a function of $[/tex]x$ is:
[tex]\[ f(x) = 2.25x + 5 \][/tex]

The correct option is the first one.