To determine the distance between two numbers on a number line, we can use the formula:
\[ \text{Distance} = |a - b| \]
where \( a = -18.26 \) and \( b = -2.45 \).
Calculating:
\[ \text{Distance} = |-18.26 - (-2.45)| \]
This simplifies to:
\[ |-18.26 + 2.45| = |-18.26 + 2.45| = |-15.81| \]
Since distance is always a positive value, we drop the negative sign:
\[ \text{Distance} = 15.81 \]
So, the correct response is:
15.81