Problem Solving
试题详情
题目：
If a code word is defined to be a sequence of different letters chosen from the 10 letters A , B , C , D , E , F , G , H , I , and J , what is the ratio of the number of 5-letter code words to the number of 4-letter code words?
选项:
A、5 to 4
B、3 to 2
C、2 to 1
D、5 to 1
E、6 to 1
答案:
E
