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## Comment on

MISSISSIPPI Rule## I would like to know, how did

How did you do the multiplication?

## Let's do some elimination.

Let's do some elimination.

First, 11! = (11)(10)(9)...(5)(4)(3)(2)(1) and 4! = (4)(3)(2)(1)

So, we have [(11)(10)(9)...(5)(4)(3)(2)(1)]/[(4)(3)(2)(1)(4)(3)(2)(1)(2)(1)]

Cancel out: [(11)(10)(9)...(5)]/[(4)(3)(2)(1)(2)(1)]

The denominator now equals 48, so rewrite it as...

[(11)(10)(9)(8)(7)(6)(5)]/[(6)(8)]

Cancel out to get: (11)(10)(9)(7)(5)

Evaluate: 34,650

## Pls how did you arrive at 20

## 5!/(3!1!1!) = (5)(4)(3)(2)(1)

5!/(3!1!1!) = (5)(4)(3)(2)(1)/(3)(2)(1)(1)(1)

= (5)(4)

= 20

Alternatively,

5!/(3!1!1!) = (5)(4)(3)(2)(1)/(3)(2)(1)(1)(1)

= 120/6

= 20

## Hi,

help on this ques plz.

In how many different ways can 3 fiction books and 3 non-fiction books be arranged in a row of 6 books on a shelf such that the fiction books are not separated, and the non-fiction books are not separated?

can I apply Mississippi rule

Thanks

## We can't use the MISSISSIPPI

We can't use the MISSISSIPPI rule here, because the objects are not identical. That is, the 3 fiction books are all different, and the 3 non-fiction books are all different.

Here's my full solution: https://gmatclub.com/forum/in-how-many-different-ways-can-3-fiction-book...

Cheers,

Brent

## Hi,

Thanks very much for the link.

Iam bit confused because it is not mentioned that the fiction books are different? will it be mentioned if the books are alike

Thanks

## That's a good point!

That's a good point!

To remove ambiguity, the question should state that the 3 books (of each type) are all different.

The linked question is not an official GRE. The official GRE test-makers would be certain to remove all ambiguity from a question like this.

Cheers,

Brent

## Thanks Brent, I hope they do

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