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- General GRE Info and Strategies - 7 videos (all free)
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- Algebra and Equation Solving - 78 videos (some free)
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- Data Interpretation - 24 videos (some free)
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## Comment on

Books on a Shelf## Can you clarify this why you

## In the solution, the first

In the solution, the first step is to select the order in which the SUBJECT blocks appear.

There are 6 ways to do this:

Math - Art - History

Math - History - Art

History - Art - Math

History - Math - Art

Art - History - Math

Art - Math - History

If we don't include this step, then we aren't account for the 6 possibilities above.

## My issue is why are we now

## In the lesson for factorials

In the lesson for factorials (https://www.greenlighttestprep.com/module/gre-counting/video/780), we learned that we can arrange n unique objects in n! ways.

So, for example, we can arrange the 3 math books in 3! ways.

Likewise, we can arrange the 2 art books in 2! ways.

etc.

Does that help?

## It does now! Thank you.

## How would the result change

## If the 7 books could be

If the 7 books could be arranged in any order, then we could accomplish this task in 7! ways.

## Why we didnt use the counting

## If you're referring to the

If you're referring to the video question above, we did use the Fundamental Counting Principle (FCP) to solve this question.

Cheers,

Brent

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