推 flac:第二個式子列錯了 應該是+1 不是-1 08/07 17:01
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46. 3960-!-item-!-187;#058&003582
How many hours did it take Helen to drive from her house to her parents' house?
(1) Helen's average speed on this trip was 72 kilometers per hour.
(2) If Helen's average speed on this trip had been 8 kilometers per hour greater, it would have taken her 1 hour less.
答案是 C
1) D/72
2) D/S = D/(S+8) -1
1)+2) 算出答案是負的
我的問題是:既然算出來答案是負的
這樣還能選C嘛? 這樣不太合邏輯。
謝謝!
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※ 編輯: piapiapia 來自: 118.167.201.56 (08/07 16:54)