陈向东代数题75题求解

jaffa23

Are there exactly 3 distinct symbols used to create the code words in language Q?
1.The set of all code words in language Q is the set of all possible distinct horizontal arrangement of one or more symbols,with no repetition.
2.There are exactly 15 code words in language Q.

答案为C。说实话，我压根理解不了。。。。

jaffa23

谢谢楼上各位

yidiyuehans

同意2楼。多读几遍题就没问题了

mudiduanger

我是没看懂ls的解释，不过条件1+2就=问题了。。。  果断c

arthurman

If there are 3 distinct symbols, we can arrange one or more of them on the

line without repetition:
1 symbol only: 3 possibilities.
2 symbols: 3*2= 6 possibilities.
3 symbols: 3*2=6 possibilites

Total possibilities = 15. 15 distint words reprented by 3 distinct symbols.

Bingo.

CCCC