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Suppose that the mean score of 28 students (in a class of 30 students) in a quiz is 28.
What should be the mean of the remaining 2 students in the class in order that the class mean is 30?
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Let the mean of the remaining 2 students in the class be x.
Then the total scores of the 30 students is 28*28 + 2x and the average of the 30 students is .
So an equation to find x is this
= 30.
Simplify and find x
28*28 + 2x = 30*30
784 + 2x = 900
2x = 900 - 784
2x = 116
x = 116/2 = 58.
ANSWER. The mean score of the remaining 2 students in the class should be 58.
Solved.