Answer:
Difference in scores between his 7th and 8th quizzes = 22
Step-by-step explanation:
Given: Mean score for first 6 quizzes is 33 points. After his 7th quiz his mean score was 32 points. After the 8th quiz the mean was 34.
To find: difference in scores between his 7th and 8th quizzes
Solution:
Mean scores = Total points scored in quizzes ÷ Number of quizzes
So,
Total points scored in quizzes = Mean scores × Number of quizzes
As mean score for first 6 quizzes is 33 points,
Total points scored in 6 quizzes = 6 × 33 = 198
As mean score for first 7 quizzes is 32 points,
Total points scored in 7 quizzes = 7 × 32 = 224
So,
7th score = Total points scored in 7 quizzes - Total points scored in 6 quizzes
= 224 - 198
= 26
As mean score for first 8 quizzes is 34 points,
Total points scored in 8 quizzes = 8 × 34 = 272
So,
8th score = Total points scored in 8 quizzes - Total points scored in 7 quizzes
= 272 - 224
= 48
Therefore,
Difference in scores between his 7th and 8th quizzes = 48 - 26
= 22
