A、B、C、D、E五人參加考試，滿分是10分，得分是整數。
A﹕「我得4分而已。」
B﹕「我得最高分。」
C﹕「我是A與D得分的平均。」
D﹕「我是五個人得分的平均。」
E﹕「我比C多2分。」
請問B得多少分?
7分 or 8分 or 9分 or 10分
解釋!!!!!!!!!!
一條數學問題
2006-12-10 1:25 am
回答 (3)
2006-12-12 1:26 am
✔ 最佳答案
By C's saying, we haveC = (A+D)/2..............(1)
By E's saying, we have
E = C+ 2..................(2)
By D's saying, we have
D = (A+B+C+D+E)/5
4D = A+B+C+E.........(3)
Sub (1) and (2) into (3), we have
4D = A+B+(A+D)/2+ (A+D)/2 +2
4D = A+B +(A+D) +2
3D = 2A + B + 2
3D = 2 x 4 + B +2 (because A = 4)
3D = B +10
B = 3D - 10
Since full mark is 10 and mark must be +ve,
D = 4, 5 or 6 (If D = 7, B = 11; wrong!)
Therefore,
If D = 4, B = 2.
If D = 5, B = 5
If D = 6, B = 8
Since B got the highest marks, the answer is that B = 8.
參考: me
2006-12-10 1:44 am
B得8分
A: 4分
B: 8分
C: 5分
D: 6分
E: 7分
A: 4分
B: 8分
C: 5分
D: 6分
E: 7分
2006-12-10 1:30 am
9分,(我)得最高分。唔係拿滿分,只是高分!
收錄日期: 2021-04-12 22:59:44
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