[smvo]

Hi,

My guesses are these:

5)

All possibilities - restrictions

(8C1*9C1) - (2C1*3C1) = 66

6)

1;2; 7-8-9;3-6-9; (3-1 OR 6-2 OR 9-3)

1*1*3C1*3C1* (1+1+1) = 27

7) b

8)

4/10 x 3/9 x 2/8 = 1/30

9)

1/X*P(b) = 1/y
p(b) = X/Y