推 lovekyoko:謝謝 10/05 22:59
※ 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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