What environment to draw frame/box compatible with floats

Question

I want to draw a text-width frame/box around a paragraph of text, like this

I used framed environment from framed package

\documentclass{article}
\usepackage{framed}
\begin{document}
    \textbf{Problem} blah, blah, ...
    \begin{framed}
        \textbf{Answer} blah blah, ...

        blah blah blah blah blah blah blah blah blah

        ...
    \end{framed}
\end{document}

But I cannot use figure, algorithm environments in this framed environment. Any solutions?

Answer 1

The float environments like figure, table others can't be placed inside other environments or boxes as they really float through the text and are placed when the TeX engine finds a good place to put them. They are not part of their surrounding code.

So if you want something framed and floating, you need to put the framing code/environment into the floating environment.

Simple example:

\documentclass{article}
\usepackage{framed}
\usepackage{lipsum} % for example text filler only
\begin{document}
\lipsum

\begin{figure}
    \textbf{Problem} blah, blah, ...
    \begin{framed}
        \textbf{Answer} blah blah, ...

        blah blah blah blah blah blah blah blah blah

        ...
    \end{framed}
\end{figure}

\lipsum
\end{document}

---

However, if you want the content of a normally floating environment on a specific spot you should not use that environment, but a non-floating replacement which gives you the same features like caption etc. without the floating effect. If so, see e.g. the nofloat key of the adjustbox package.