How to arrange a page as two colum? (similar to multicols)

There a some math problems& answers, I want to show them in two columns as following:

But I have no idea how to implement this function.

I have tried tabular and multicols, however these commands didn't work as I expected.

Any help would be appreciated!

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Can you please post what you have tried so far? – Harish Kumar Dec 9 '12 at 12:20
It depends on the class you are using but with the basic article class, the twocolumn option (hence \documentclass[twocolumn]{article} in your preamble) may help, unless you are trying to achieve something different.. – Corentin Dec 9 '12 at 12:24
A (long)table containing parboxes would probably the easiest and most flexible approach. – Stephan Lehmke Dec 9 '12 at 15:21

I believe this might work. We put two minipages on a line, the code is different from left(=odd, we start a paragraph there) and right(=even, we make a horizontal space before and vertical space after) Q&A

I hope that the usage is clear. We added \raggedbottom to allow the pages to be underfull.

\documentclass{article}

\raggedbottom

\newcounter{QA}
\newcommand\QA[2]{
\refstepcounter{QA}
\ifodd\arabic{QA}
\par\noindent\begin{minipage}[t]{0.47\textwidth}
\else
\hspace{0.06\textwidth}\begin{minipage}[t]{0.47\textwidth}
\fi
\textsf{\bfseries Q\arabic{QA}:}\hspace{0.3em plus 0.2em minus 0.1em}\ignorespaces#1
\smallskip\par
\textsf{\bfseries A\arabic{QA}:}\hspace{0.3em plus 0.2em minus 0.1em}\ignorespaces#2
\ifodd\arabic{QA}
\end{minipage}\ignorespaces
\else
\hspace{0.06\textwidth}\end{minipage}
\bigskip\par
\fi
}

\begin{document}

\QA{
Why $42$?
}{
Because $42=\int_0^{42}1 dx$.
Because $42=\int_0^{42}1 dx$.
Because $42=\int_0^{42}1 dx$.
Because $42=\int_0^{42}1 dx$.
Because $42=\int_0^{42}1 dx$.
Because $42=\int_0^{42}1 dx$.
}
%
\QA{
Why $43$?
}{
Because it is a prime number.
}
%
\QA{
Why $44$?
}{
Because it is a palindrome.
}

\end{document}

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