SOLUTION: I 8. Marlon has a mean score of 82 in 4 Statistics quizzes. Another 100 - item quiz will be given tomorrow. What should be Marlon’s score so that his mean score in the 5 quizze

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Question 1159081: I 8. Marlon has a mean score of 82 in 4 Statistics quizzes. Another 100 - item quiz will be given tomorrow. What should be Marlon’s score so that his mean score in the 5 quizzes will be 85?
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

%284%2A82%2Bx%29%2F5 = 85


4*82 + x = 5*85


x = 5*85 - 4*82 = 97.      ANSWER

Solved.



Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Here is a different, less formal method for solving this kind of problem dealing with averages of numbers that are all close together.

The mean of 82 on 4 quizzes effectively means he has 4 scores of 82.
Each of those scores is 3 points below the average he wants; so all together they are 4*3=12 points below what he wants.
To get the average he wants, that fifth quiz must be 12 points above the desired average, to balance the 12 points he is currently short.

ANSWER: 85+12 = 97