Question 245898
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If the average score for 10 boys is 80, then the total score for the 10 boys must be 800.  If the average score for 15 girls is 90, then the total score for the 15 girls must be 1350.  That means the total score for the 25 students must be 800 plus 1350 equals 2150.  Divide 2150 by 25 to get the average for the whole class.  As a check on your arithmetic, common sense says that the answer has to be larger than 80 but smaller than 90.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
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