GWD 04-05

[wisson0927]

If a code word is defined to be a sequence of dfifferent letters chosen from the 10 letters A, B, C D, E, F, H, I N,and J, what is the ratio of the number of 5-letter code words to the number of 4-letter code words?
A. 5 to 4
B. 3 to 2
C. 2 to 1
D. 5 to 1
E. 6 to 1

ans:E

請問一下，這要如何解呢？
謝謝!!!

[homaru]

http://www.formosamba.com/phpBB3/viewtopic.php?t=4257
抱歉
版主這題之前沒做連結
已補上

[wisson0927]

好的...謝謝!!!