Question 317434

Billy takes two marbles, without replacement, from a bag that contains only six yellow marbles and three blue marbles. What is the probability that he gets one marble of each color? Express your answer as a common fraction.
<pre><b>
AND implies multiplication and OR implies addition:

P[(Blue 1st AND Yellow 2nd) OR (Yellow 1st AND Blue 2nd)] =
  ( 3/9      ×     6/8    )  + (    6/9     ×    3/8   )  =
                 {{{(3/9)(6/8)+(6/9)(3/8)}}}
                 {{{(1/3)(3/4)+(2/3)(3/8)}}}
                 {{{(1/cross(3))(cross(3)/4)+(2/cross(3))(cross(3)/8)}}}
                 {{{1/4+2/8}}}
                 {{{1/4+1/4}}}
                 {{{2/4}}}
                 {{{1/2}}}
Edwin</pre>