S1-20. When 9 students took a zoology quiz with a possible score of 0 to 10, inclusive, there average (arithmetic mean) score was 7.5. If a tenth student takes the same quiz, what will be the least possible average score on the quiz for all 10 students?
(A) 6.5
(B) 6.75
(C) 7.0
(D) 7.25
(E) 7.5
答案B
我选A 因为根据0~10的分数范围 算出possible average score 的范围是6.75~7.5。