[BruceZ]

[ QUOTE ]
3*36/1225 -
C(3,2)*36*30 / C(50,2) / C(48,2) +
C(3,3)*36*(6*25+24*24) / C(50,2) / C(48,2) / C(46,2)

=~ 8.58%.

[/ QUOTE ]

Slight correction to 3rd line:

3*36/1225 -
C(3,2)*36*30 / C(50,2) / C(48,2) +
C(3,3)*36*(6*26+24*24) / C(50,2) / C(48,2) / C(46,2)

=~ 8.58%.