The first question is 1/4, and two of the eight items meet the requirements.

① A, B and C are all in A, B, C in B, C in A, B in B, C in A and A in B..

Party A, Party B and Party C are all in B5A, Party B is in A7A, Party C is in B and Party C is in A..

The probability that P (A, b, c) all appear in the same restaurant is 1/4.

the second question

From the above scheme, we can get 23456 ⑧ ⑧ ⑧ ⑧ ⑧ ⑧ ⑧ ⑧.

So P (at least one of Party A, Party B and Party C dines in Restaurant B) =7/8.

Hey hey, the pig has grown up. . Give it to me, hehe. You can't make me type so many words for nothing. (* _ _ *) Hee hee ...