數學求解
If m is a positive integer, how many positive integers are factors of m?
(1) m is the product of 4 different prime numbers
(2) m < 41
答案是 (C) Both statement together are sufficient, but neither statement alone
is sufficient.
可是為什麼只看 (1)不能決定?
四個質數相乘不就有 2*2*2*2 = 16個因數嗎
McGraw詳解寫 statement one is insufficient because there is (probably) an
infinate number of prime numbers, so there is an infinate range of values
for m.
可是m的大小跟幾個因數有關係嗎 是我理解錯誤嗎?
請各位幫忙
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