Select the correct answer.

A coffee shop begins the day with 75 bagels and sells an average of 10 bagels each hour. Function [tex]b[/tex] models the bagel inventory, [tex]b(x)[/tex], [tex]x[/tex] hours after opening.

[tex] b(x) = 75 - 10x [/tex]

If the coffee shop wants to make a graph of function [tex]b[/tex], which values of [tex]x[/tex] should it include on the graph to include the relevant domain within the context?

A. [tex]0 \leq x \leq \infty[/tex]
B. [tex]0 \leq x \leq 7.5[/tex]
C. [tex]-\infty \leq x \leq \infty[/tex]
D. [tex]0 \leq x \leq 75[/tex]



Answer :

To determine the correct range of values for [tex]\( x \)[/tex] that should be included in the graph of the bagel inventory function [tex]\( b(x) = 75 - 10x \)[/tex], let's analyze the context:

1. Initial Inventory and Rate of Sale:
- The coffee shop starts with 75 bagels.
- The shop sells bagels at a rate of 10 bagels per hour.

2. Understanding the Function [tex]\( b(x) \)[/tex]:
- [tex]\( b(x) = 75 - 10x \)[/tex] represents the bagel inventory [tex]\( x \)[/tex] hours after opening.
- When [tex]\( x = 0 \)[/tex] (shop opens), the inventory is [tex]\( b(0) = 75 \)[/tex].
- Each hour, the inventory decreases by 10 bagels.

3. Finding the Point When Inventory Depletes:
- To find when the inventory will reach zero:
[tex]\[ 75 - 10x = 0 \][/tex]
Solve for [tex]\( x \)[/tex]:
[tex]\[ 75 = 10x \][/tex]
[tex]\[ x = \frac{75}{10} = 7.5 \][/tex]

4. Determining Relevant Domain:
- The values of [tex]\( x \)[/tex] should start from 0 (when the shop opens) and go up to 7.5 hours (when the inventory is depleted).

Therefore, the correct range of [tex]\( x \)[/tex] values to include in the graph of the function for the relevant domain of the context is:

B. [tex]\( 0 \leq x \leq 7.5 \)[/tex]