1 There are 4× 3× 2× 1 = 24 ways for four people to take away greeting cards. Four people have nine ways to get cards that don't belong to them, because the first person has three ways to get cards, and the remaining three people have only three ways to get cards that don't belong to them. No matter which card the first person holds, there are only three ways for the remaining three people to get a card that doesn't belong to them, so 3× 3 = 9. P=9/24=3/8

If the arrival time is within 20 minutes after the bus leaves, and you can't wait for the bus within 10 minutes, the waiting probability for the bus exceeding 10 minutes is 20/30 = 2/3, and the waiting probability for the bus less than 10 minutes is130 = 65438+. Give the best ~ ~ Do it seriously ~ ~ Work hard ~ ~ No guarantee for reference ~ ~ ~