To rearrange the formula \( X = mb \) for \( m \), you need to isolate \( m \) on one side of the equation.
Starting with the original equation:
\[ X = mb \]
You can solve for \( m \) by dividing both sides by \( b \):
\[ m = \frac{X}{b} \]
So the rearranged formula, with \( m \) as the quantity of interest, is:
\[ m = \frac{X}{b} \]