Cozy Closet children's store is having its annual winter sale, during which every item in the store is marked down. During the sale, pajama sets sell for [tex]$7[/tex] less than the full price. Mr. Dorsey purchases 3 matching pajama sets, one for each of his children. He pays a total of [tex]$57[/tex].

Which equation can you use to find how much money, [tex]f[/tex], each pajama set costs at full price?

A. [tex]7(f-3)=57[/tex]

B. [tex]3f-7=57[/tex]

C. [tex]3(f-7)=57[/tex]

D. [tex]7f-3=57[/tex]

To solve this problem, we want to find out the full price of each pajama set. Let's break down the information:

1. Information Given:
- Mr. Dorsey buys 3 pajama sets.
- Each set is marked down by [tex]$7 from its full price.
- He pays a total of $[/tex]57 for 3 sets.

2. Define the Variables:
- Let [tex]$ f $[/tex] be the full price of one pajama set.

3. Express the Discounted Price:
- Since each pajama set is sold for [tex]$7 less than the full price, the sale price of one set is $ f - 7 $.

4. Total Cost Calculation:
- Since Mr. Dorsey buys 3 sets, the total cost for the discounted sets is:
\[
3 \times (f - 7)
\]
- According to the problem, Mr. Dorsey paid a total of $[/tex]57, so we set up the equation:
[tex]\[
3 \times (f - 7) = 57
\][/tex]

5. Equation Option:
- The correct equation to find the full price [tex]$ f $[/tex] is:
[tex]\[
3(f - 7) = 57
\][/tex]

This equation directly correlates with the conditions given in the problem and matches the correct choice from the options provided.