I would like to use a multicol package and create three columns with different widths, e.g. 30%, 30% and 40% of the total \textwidth.
How to do this?
More concretely, I am also using
\columnbreak and I have three distinct sections that I want to see on one page split vertically and flushed left each separately. However, I want them to have different widths, small separation and distinct division like a full vertical line.