※ 引述《lovekyoko (我在Tamap 天氣晴)》之銘言： : What is the value of the positive integer m ? : (1) When m is divided by 6, the remainder is 3. : (2) When 15 is divided by m, the remainder is 6. : 答案B : 我知道A不充分 但B為啥充分阿 : 我是這樣列式的 15=mx+6 變數有2個 這樣可以充分嗎?? (1) m=6x+3 x=1~ (2) 15=mx+6 又m必須為正值 故m必定為1~9之中無法整除15的數值 會整除:1,3,5,7 會餘1:2,7 會餘7:8 只剩下9....(B)為正解 : Sets A, B, and C have some elements in common. If 16 elements are in both A : and B, 17 elements are in both A and C, and 18 elements are in both B and C, : how many elements do all three of the sets A, B, and C have in common? : (1) Of the 16 elements that are in both A and B, 9 elements are also in C. : (2) A has 25 elements, B has 30 elements, and C has 35 elements. : 答案A : 我也知道B不充分 但A哪裡有充分?? : 謝 (1) A與B有公因數16個(其中也包含了A與B與C的公因數) 它又提到在這16個裡頭有9個是跟C有關的....那這9個當然就是A,B,C的公因數 <可以用圓餅圖去想一想> 不知道這樣解釋對不對... --

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