Lesson: Factoring – Greatest Common Factor

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
gmat-admin's picture

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 !
gmat-admin's picture

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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