Please, next time, please share the graph referred to in the problem statement.
You are comparing f(x)=2 ln x and g(x) = 4 ln x. The two graphs look the same, except that the amplitude (rise) in 4 ln x is exactly twice that in 2 ln x.
Thus, if 2 ln x = 3, 4 ln x = 2(3) = 6.