AMC8 2016
AMC8 2016 · Q3
AMC8 2016 · Q3. It mainly tests Averages (mean).
Four students take an exam. Three of their scores are 70, 80, and 90. If the average of their four scores is 70, then what is the remaining score?
四个学生参加考试。其中三个分数是70、80和90。如果四个分数的平均分是70，那么剩下的分数是多少？
(A)
40
40
(B)
50
50
(C)
55
55
(D)
60
60
(E)
70
70
Answer
Correct choice: (A)
正确答案：（A）
Solution
The given scores 70, 80, and 90 are a total of 30 above the stated average. Thus the remaining score is 30 points below the average, and $70-30=40$.
给出的分数 70、80 和 90 相对于所给平均分总计高出 30 分。因此剩下那次分数应比平均分低 30 分，于是 $70-30=40$。
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