※ 引述《zila (信心花舍)》之铭言： : The scores reported for a certain multiple-choice test were derived by : subtracting 1/3 of the number of wrong answers from number of right answers. : On a 40-question test, if none of the questions was ommited and the score : reported was 20, how many wrong answers were there? : A. 5 : B. 10 : C. 15 : D. 25 : E. 30 : ans. C : 感谢解答~~ 解题方法一 代数 设 错题数目为X 根据假设 即全部都有写 那对的题目数目为 40-X 所以分数 = (40-X)-1/3*X = 20 解得 X = 5 解题方法二 代选项 假设都跟上述一样 那只有有三的倍数的答案 会有整数的分数吧 所以剩下C和E 代吧 第一次回答GRE数学 请多包涵指教 --

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