On Wednesday, 11 Oct 2017 at 10:03, Jeremie Juste wrote:
> Hello,
>
> I'm making some exercices with answers and I'm writing the answers just
> after the questions in the following way

[...]

> There is an interesting package that does something similar in latex
> https://ctan.org/pkg/probsoln. you can access it here after unzipping.

Probably the easiest way is to use this LaTeX class and enclose the
solutions in an org special block:

--8<---------------cut here---------------start------------->8---
#+latex_header: \usepackage{probsoln}
* first question
Do something.
#+begin_solution
here goes your solution
#+end_solution
--8<---------------cut here---------------end--------------->8---


-- 
: Eric S Fraga via Emacs 27.0.50, Org release_9.1.2-98-g0b8316