Suppose your friend was using the Simple Linear Regression Model:
$$y_i = \beta_0 + \beta_1 x_i + u_i$$
...which she estimated via OLS. Both the $y_i$ and $x_i$ variables were measured in meters. Her estimate for the slope term was $-238.9$.
She then decided to rescale one of the variables into kilometers instead of meters -- but you don't know which one. All you know is her rescaled estimate for the slope term is $-0.2389$.
Which variable did she rescale?