What is the total number of different 5-digit numbers that contain all of the di

游客2024-01-12  22

问题 What is the total number of different 5-digit numbers that contain all of the digits 2,3, 4, 7 and 9 and in which none of the odd digits occur next to each other?

选项 A、12
B、10
C、8
D、6
E、1

答案 A

解析 含有2,3,4,7和9这5个不同数字,且奇数不相邻的5位数(5-digit numbers)的总数是多少?
解:本题的正确答案是(A)。这5个数中有三个奇数,不相邻时它们应分别在个位,百位和万位,剩下2,4在十位和千位,由题意可得:
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