<PRE><B>Question 1204991</B>
A teacher wants to calculate the average score of her students. She has the scores of 20 students, but she accidentally misplaced one score. If the average of the remaining 19 scores is 85, what should be the misplaced score to maintain a weighted mean of 87?

The average of the 19 students is 85 as calculated by teacher
So total score = 19*85 =1615

Let the misplace score be x

Total score of 20 students will be 1615+x
The average is 87
The average now is (1615+x)/20= 87

1615+x = 87*20

1615+x= 1740

x = 1740-1615

x =125


 The misplaced score  is 125 to maintain a mean of 87.

CHECK

1615+125 =1740

1740/20=87

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