Question

Ally has taken 5 quizzes this year. Her mean quiz score is 8 out of 10. She takes another quiz and gets a perfect score of 10.
What happens to her mean score?
The mean increases by 2.
The mean increases by 0.33.
The mean does not change.
The mean decreases by 5.

Answer 1

Initial total = 5 × 8 = 40.
After a 10, new total = 50 and new mean = 50/6 = 8 1/3 ≈ 8.33.
So the mean increases by 1/3 ≈ 0.33.