To solve the problem, we have the following system of equations based on the information given:
- \( x + y = 28 \) (The total number of boxes sold by Jennifer and Marci)
- \( y = 2x - 5 \) (Marci sold 5 less than twice the number sold by Jennifer)
Now, we will substitute the second equation into the first.
Substituting \( y = 2x - 5 \) into \( x + y = 28 \):
\[ x + (2x - 5) = 28 \]
Combine like terms:
\[ 3x - 5 = 28 \]
Add 5 to both sides:
\[ 3x = 33 \]
Now, divide by 3:
\[ x = 11 \]
Now that we have \( x \) (the number of boxes sold by Jennifer), we can find \( y \) (the number sold by Marci) using the first equation:
\[ y = 28 - x = 28 - 11 = 17 \]
So, Jennifer sold 11 boxes and Marci sold 17 boxes.
Thus, the final answer is:
D: Marci sold 17 boxes and Jennifer sold 11 boxes.