推 Ertai:題目不是說 n>20了 考慮17 19幹嘛0.0? 11/02 12:52
→ pei33ho:阿～算到中邪～謝謝喔!!! 11/02 12:58
136. 13960-!-item-!-187;#058&009782
An integer greater than 1 that is not prime is called composite.
If the two-digit integer n is greater than 20, is n composite?
(1) The tens digit of n is a factor of the units digit of n.
(2) The tens digit of n is 2.
答案A
想問(1)不能包含17.19這類數字嗎?總覺得17.19這種算是反例呀?
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