A travel agency provided four tour routes for three tour groups to visit the Garden Expo Park. Choose one for each tour group, (1) let three tour groups choose three.

Three tour groups provide four tour routes to visit the Garden Expo Park, and each tour group can choose one of them in 43=64 ways.

(1) Note: "Three tour groups choose three different routes" as event A, then the result of A is A34 = 24.

∴P(A)=2464=38

(2) Note: "Just two lines are not selected" is event B, and the result of B is C24C23A22=36.

∴P(B)=3664=9 16

(3) Let the number of tour groups choosing Route A be X, and the value of X is 0, 1, 2, 3.

P(X=0)=3364=2764

P(X= 1)=C 13？ 3264=2764

P(X=2)=3C2364=964

P(X=3)= 164

EX = 0×2764+ 1×2764+2×964+3× 164 = 2332