14.Suppose you place 5 coins at random on squares of a 5 \x02 5 grid (so there are 25 squares),with no two coins permitted to occupy the same square.(a) What is the probability that no two coins are placed in the same row?(b) What is the probability that no two coins are placed in the same row,and no twocoins are placed in the same column?
问题描述：
14.Suppose you place 5 coins at random on squares of a 5 \x02 5 grid (so there are 25 squares),
with no two coins permitted to occupy the same square.
(a) What is the probability that no two coins are placed in the same row?
(b) What is the probability that no two coins are placed in the same row,and no two
coins are placed in the same column?
答
no two coins in the same square：C(25,5)
each row one coin：5^5
no same row or column,：5!