Question 593649
<pre>
{{{p(

(matrix(5,1,

drawing, a, red, sock, first)

matrix(5,1,

"", "", AND, "", "")

matrix(5,1,

drawing, a, red, sock, second))

matrix(5,1,

"", "", OR, "", "")

(matrix(5,1,

drawing, a, blue, sock, first)

matrix(5,1,

"", "", AND, "", "")

matrix(5,1,

drawing, a, blue, sock, second))))
)}}}

Use the principle that "AND" goes with "multiply" and 
"OR" goes with ADDITION:

{{{p(

matrix(5,1,

drawing, a, red, sock, first) )*

p(

matrix(5,1,

drawing, a, red, sock, second) )}}} + {{{p(

matrix(5,1,

drawing, a, blue, sock, first) )*
p(

matrix(5,1,

drawing, a, blue, sock, second) ) )

}}} =

{{{9/13}}}·{{{8/12}}} + {{{4/13}}}·{{{3/12}}} =

{{{9/13}}}·{{{2/3}}} + {{{4/13}}}·{{{1/4}}} =

{{{18/39}}} + {{{1/13}}} =

{{{6/13}}} + {{{1/13}}} =

{{{7/13}}}

Edwin</pre>