1) Letters of CINCINNATI are rearranged to form new "words". Find the number of words if
a. there is no restriction
b. same letters are put together
c. the first letter and the last letter are different.
2) 10 persons are randomly selected form 10 couples to play a game. Find the number of ways if
a. there is no restriction
b. they are of same sex
c. there are equal number of male and female
d. there are exactly 2 couples
發表於 09-10-30 07:02 PM