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## Comment on

Factoring – Greatest Common Factor## Hi Brent,

Could you please help me solve this problem.

Thank you.

A certain list consists of 21 different numbers. If n is in the list and n is 4 times the average (arithmetic mean) of the other 20 numbers in the list, then n is what fraction of the sum of the 21 numbers in the list?

1/20

1/6

1/5

4/21

5/21

## Here's my full solution:

Here's my full solution: https://gmatclub.com/forum/a-certain-list-consists-of-21-different-numbe...

Aside: In the future, please post your questions under the related video lesson.

This question is about averages (means). So, it would have gone well under the Statistics lesson on Averages/Means

Cheers,

Brent

## Hi Brent,

Could you please explain how to factorise an expression into two binomials or into polynomial. In the video you have shown only how to factorise monomial.

Thanks in advance !

## The above lesson on Greatest

The above lesson on Greatest Common Factor factoring is the first of 4 lessons on factoring.

You'll find what you need in the next 3 lessons.

Cheers, Brent

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