Question 731105
.
A bag contains 12 red and 8 blue marbles. If you randomly select 2 marbles, what is the probability 
that they are the same color?
~~~~~~~~~~~~~~~~~~~~~~~



<pre>
P = P(red,red) + P(blue,blue) = {{{(12/20)*(11/19)}}} + {{{(8/20)*(7/19)}}} = {{{(12*11+8*7)/(20*19)}}} = {{{188/380}}} = {{{47/95}}} = 0.4947  (rounded).    <U>ANSWER</U>
</pre>

Solved.


------------------------


The answer in the post by @lynnlo is incorrect.
Simply ignore his post.