To find Joe's score, we can set up the equation based on the information provided:
\[ 24 + \text{Joe's score} = 48 \]
To solve for Joe's score, we subtract 24 from both sides:
\[ \text{Joe's score} = 48 - 24 \]
Calculating the right side gives:
\[ \text{Joe's score} = 24 \]
Therefore, Joe's score is 24.