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, 2023

Algebra Difficulty 1.5 Junior Find the answer Canada

Suppose $n$ is a number such
that the mean (average) of the list of numbers $2, 9, 4, n, 2n$ is equal to $6$ . What is the value of $n$ ?

Pick one

Solution

The given list, $2,9,4,n,2n$
contains 5 numbers.

The average of these 5 numbers is 6, and so the sum of the 5 numbers is
$5\times 6=30$ .

That is, $2+9+4+n+2n=30$ or $15+3n=30$ , and so $3n=15$ or $n=5$ .

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Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project.