单选题 The incomplete table above shows a distribution of scores for a class of 25 students. If the average (arithmetic mean) score for the class is 83, what score is missing from the table?

Score	Number of students
92	4
91	6
?	3
83	7
71	5

A. 75
B. 77
C. 81
D. 84
E. 86

【正确答案】 A

【答案解析】If the average score for the class is 83, then the sum of all 25 students' scores be 83×25=2,075. The sum of the scores for the 22 students for whom we have scores is 368+546+581+355=1,850. So the three students' scores must make up the difference between 2,075 and 1,850; 2,075-1,850=225; 225/3=75.