对11月份数学机井25题和32题答案质疑、探讨

micklefuUID: 185916

25. n is the product of four prime numbers, in which, two are the same. how many divisors, including n and 1 does n have.答案有一个是比九小的，有一个是九，有一个是十二，还有一个好象是十六。
【答案1】12； 因为里面有2个重复的因子，所以问题复杂了些全部因子=1+C(4,1)+C(4,2)+C(4,3)+C(4,4)=16
重复因子=1+ C(2,1)+C(2,2) =4
16-4=12
【我的答案】9； 1，a,b,c,n; 5+c(3,2)+c(3,3)=5+3+1=9



32.xyz都是质数, 问最多有多少因子?
(2*2*2=

whoeverioeUID: 170170

1)to save time take 90 as an example, 90=2*3*3*5, and it's got 12 divisors(1,2,3,5,6,9,10,15,18,30,45,90), so there we go, 12 is correct.


2)I dont understand the question

micklefuUID: 185916

谢谢解答！！！不胜感激！！！