For grouped data, the relationship between the mean (\( M \)), median (\( Md \)), and mode (\( Mo \)) is given by:
\[
Md = \frac{3M - Mo}{2}
\]
Step 1: Substituting the given values.
We are given:
- Mean (\( M \)) = 24
- Mode (\( Mo \)) = 12
Substitute these values into the formula for the median:
\[
Md = \frac{3 \times 24 - 12}{2} = \frac{72 - 12}{2} = \frac{60}{2} = 30
\]
Step 2: Conclusion.
Therefore, the median of the data is 20.