To find the numerical length of NO, we first note that since point O is on line segment NP, we can express the relationship between the segments using the provided information:
- \( NP = NO + OP \)
By substituting the given values into this equation, we have:
\[ 2x = NO + 10 \]
We are also given that:
\[ NO = x + 7 \]
Now, we can substitute \( NO \) in the equation for \( NP \):
\[ 2x = (x + 7) + 10 \] \[ 2x = x + 17 \]
Now, subtract \( x \) from both sides:
\[ 2x - x = 17 \] \[ x = 17 \]
Now that we have the value of \( x \), we can substitute it back into the equation for \( NO \):
\[ NO = x + 7 \] \[ NO = 17 + 7 \] \[ NO = 24 \]
Thus, the numerical length of \( NO \) is \( \boxed{24} \).