The average number of students per class at school X is 25 and the average number of students per class at school Y is 33. Given that there are more classes in school X than in school Y, is the average number of students per class for both schools combined less than 29?

Ruby Briggs 2022-07-23 Answered
The average number of students per class at school X is 25 and the average number of students per class at school Y is 33. Given that there are more classes in school X than in school Y, is the average number of students per class for both schools combined less than 29?
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Answers (1)

frisiao
Answered 2022-07-24 Author has 13 answers
Let N 1 , N 2 be number of classes in the first and the second schools respectively. Then number of students in the first school is 25 , N 1 and in the second school is 33 , N 2, so the average students per class is ( 25 N 1 + 33 N 2 ) / ( N 1 + N 2 ) Let's see when it is < 29:
( 25 N 1 + 33 N 2 ) / ( N 1 + N 2 ) < 29
25 N 1 + 33 N 2 < 29 ( N 1 + N 2 ) = 29 N 1 + 29 N 2
4 N 2 < 4 N 1
N 2 < N 1
As per more general question, a "simple" average implies equal weights,if the weight of a "lower" part is higher, the weighted average will be less than the simple average.
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