7. If a book costs [tex]$\$[/tex]12[tex]$ and the shipping cost is $[/tex]\[tex]$3$[/tex] per book, what is the total cost [tex]$T$[/tex] for [tex]$b$[/tex] books?

A. [tex]$T = 3b - 12$[/tex]
B. [tex]$T = 12b$[/tex]
C. [tex]$T = 15b$[/tex]
D. [tex]$T = 12 + 3b$[/tex]



Answer :

Sure, let's break down the question step by step to find the total cost [tex]\(T\)[/tex] for [tex]\(b\)[/tex] books.

1. Cost per book:
The cost of one book is [tex]$12. 2. Shipping cost per book: The shipping cost per book is $[/tex]3.

3. Combining the costs:
For each book, you have to pay both the cost of the book and the shipping cost. So, the total cost for one book is:
[tex]\[ 12 + 3 \][/tex]
Simplifying this:
[tex]\[ 15 \][/tex]
So, the total cost for each book, including shipping, is $15.

4. Total cost [tex]\(T\)[/tex] for [tex]\(b\)[/tex] books:
If you buy [tex]\(b\)[/tex] books, you need to multiply the total cost per book by the number of books:
[tex]\[ T = 15b \][/tex]

Therefore, the correct formula for the total cost [tex]\(T\)[/tex] for [tex]\(b\)[/tex] books is:
[tex]\[ T = 15b \][/tex]

Hence, the correct answer is:
[tex]\[ T = 15b \][/tex]