Question #N1007

A group of 20 students took a test. The average score of the students was 75. One student's score was accidentally recorded as 80 instead of 60. What is the actual average score of the students?
A. 74
B. 74.5
C. 75.5
D. 76

Correct Answer is: A

The incorrect score of 80 is 20 points higher than the actual score of 60. Since the average is the sum of the scores divided by the number of scores, the incorrect score inflated the total sum of the scores by 20. Therefore, the actual total sum of the scores is 20 points lower than the incorrect total. The actual average score is (20 * 75 - 20)/20 = 74.