Question 550546
<pre>
[-2011, 2012]

There are 2012 positive numbers, and 2011 negative numbers, and 1 zero.

So there are 2012+2011+1 or 4024 numbers to choose from.

We have to choose a pair of positive numbers or a pair of negative numbers.

If we choose the numbers with replacement:

P[(positive 1st AND positive 2nd) OR (negative 1st AND negative 2nd)] =

P(positive 1st)×P(positive 2nd) + P(negative 1st)×P(negative 2nd)

If the choosing of the numbers is done with replacement

{{{2012/4024}}}×{{{2012/4024}}} + {{{2011/4024}}}×{{{2011/4024}}}

which works out to be {{{4023/8050}}} = .4997515528

If the choosing of the numbers is done without replacement

{{{2012/4024}}}×{{{2011/4023}}} + {{{2011/4024}}}×{{{2010/4023}}}

which works out to be .4996272675

Edwin</pre>