选择题
2016 AMC 8 Problem 3: Missing Exam Score
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?
2016 AMC 8 第3题：缺少考试分数
四名学生参加考试。他们中的三个人的分数分别是70、80和90。如果他们四个人的平均分数是70，那么剩下的分数是多少
A.
40
B.
50
C.
55
D.
60
E.
70