What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?

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The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  28 Oct 2013, 04:26

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?

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What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
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What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
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The number of arrangement of letters of the word BANANA in which the two N's do not appear adjacently is:

A. 40
B. 50
C. 60
D. 80
E. 100

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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  28 Oct 2013, 06:03

saurabhprashar wrote:

The number of arrangement of letters of the word BANANA in which the two N's do not appear adjacently is:

A. 40
B. 50
C. 60
D. 80
E. 100

Total # of arrangements of BANANA is 6!/(3!2!) = 60 (arrangement of 6 letters {B}, {A}, {N}, {A}, {N}, {A}, where 3 A's and 2 N's are identical).

The # of arrangements in which the two N's ARE together is 5!/3!=20 (arrangement of 5 units letters {B}, {A}, {A}, {A}, {NN}, where 3 A's are identical)..

The # of arrangements in which the two N's do not appear adjacently is {total} - {restriction} = 60 - 20 = 40.

Answer: A.
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What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  14 Oct 2018, 04:31

Bunuel
These types of multinomial questions are great.
Is there a name for when two objects can't be adjacent to each other in combinations/permutations? It's a rule that I always forget how to apply.
A long shot, but do you know the source for OPs question?

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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  14 Oct 2018, 08:20

philipssonicare wrote:

Bunuel
These types of multinomial questions are great.
Is there a name for when two objects can't be adjacent to each other in combinations/permutations? It's a rule that I always forget how to apply.
A long shot, but do you know the source for OPs question?

I call these questions MISSISSIPPI questions.
To see why, see my post below

Cheers,
Brent
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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  14 Oct 2018, 08:30

saurabhprashar wrote:

The number of arrangement of letters of the word BANANA in which the two N's do not appear adjacently is:

A. 40
B. 50
C. 60
D. 80
E. 100

---------ASIDE-------------
When we want to arrange a group of items in which some of the items are identical, we can use something called the MISSISSIPPI rule. It goes like this:

If there are n objects where A of them are alike, another B of them are alike, another C of them are alike, and so on, then the total number of possible arrangements = n!/[(A!)(B!)(C!)....]

So, for example, we can calculate the number of arrangements of the letters in MISSISSIPPI as follows:
There are 11 letters in total
There are 4 identical I's
There are 4 identical S's
There are 2 identical P's
So, the total number of possible arrangements = 11!/[(4!)(4!)(2!)]
-------ONTO THE QUESTION!!---------------------------------

In BANANA, there are:
There are 6 letters in total
There are 3 identical A's
There are 2 identical N's
So, the total number of possible arrangements = 6!/[(3!)(2!)]
= 60

IMPORTANT: Among these 60 outcomes, there are some outcomes that break the rule about N's not appearing next to each other.
So, let's determine the number of outcomes in which the 2 N's ARE together, and we'll subtract this from our 60 outcomes.

First "glue" the 2 N's together, to get one "super letter" NN
So, we now must arrange 5 letters: B, A, A, A, and NN
There are 5 letters in total
There are 3 identical A's
So, the total number of possible arrangements = 5!/(3!)
= 20

Number of arrangements that adhere to the rule = 60 - 20 = 40

Answer: A

Cheers,
Brent
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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  28 Apr 2019, 04:47

Hi Bunuel,
Could you please confirm that while calculating restriction why we do not take into account reciprocal of {N1N2} i.e.{N2N1}?
Is that because the reciprocal/repetition has already been excluded from the total combinations (by dividing 2!)?
Thanks.

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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  28 Apr 2019, 04:49

Hi Bunuel
Could you please confirm that while calculating restriction why we do not take into account reciprocal of {N1N2} i.e.{N2N1}?
Is that because the reciprocal/repetition has already been excluded from the total combinations (by dividing 2!)?
Thanks.

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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  02 Jun 2019, 01:22

saurabhprashar wrote:

The number of arrangement of letters of the word BANANA in which the two N's do not appear adjacently is:

A. 40
B. 50
C. 60
D. 80
E. 100

BANANA =
arrangement = 6!/2!*3!= 60 ways
and NNAAAB
NN=X
XAAAB = 5!/3! = 20 ways
totaal N is together ; 60-20 ; 40 ways
IMO A

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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  12 Sep 2020, 06:28

Total number of ways to arrange the letters of the given word BANANA : \(\frac{(6!) }{ (3! * 2!)}\) = 60

Number of ways if both NN are adjacent: Consider 'NN' as 1 letter: BAAA (NN)

=> We have 5 letters to arrange, therefore: 5!.

=> Both 'NN' can be arranged it 2! ways. As we have repetition (3A's and 2N's) therefore:

=> \(\frac{(5!) *(2!) }{ (3! * 2!)}\) = 20

The number of ways 'NN' won't be adjacent to each other: 60 - 20 = 40.

Answer A
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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  19 Sep 2020, 08:14

YassiHASHMI wrote:

Hi Bunuel
Could you please confirm that while calculating restriction why we do not take into account reciprocal of {N1N2} i.e.{N2N1}?
Is that because the reciprocal/repetition has already been excluded from the total combinations (by dividing 2!)?
Thanks.

We don't consider N2N1 as a different arrangement since the two letters "N" are identical. There is no difference in the arrangement if you swap the positions of N.

Hope it is clear.

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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  29 Jan 2021, 14:49

6! / 3! x 2! = 60 <--- Total # of permutations with repeats
5! / 3! = 20 <--- Total # of permutations where Ns are TOGETHER

60 - 20 = 40 <--- Ps where they are not together

Answer is A.
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Re: The number of arrangement of letters of the word BANANA in [#permalink]

What is the number of ways of arrangement of letters of the word BANANA so that no two ns are together?
  15 Aug 2022, 08:19

arrangement = 6!/2!*3!= 60 ways
and NNAAAB
NN=X
XAAAB = 5!/3! = 20 ways
totaal N is together ; 60-20 ; 40 ways

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Re: The number of arrangement of letters of the word BANANA in [#permalink]

15 Aug 2022, 08:19

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How many arrangements are there of the letters BANANA such that no two n's appear in adjacent positions?

Hence number of way in which two N′s do not appear adjacently =60−20=40.

How many ways can the letters of BANANA be arranged?

So 60 distinguishable permutation of the letters in BANANA.

How many permutations of the letters of the word BANANA are possible?

m! In the word BANANA, we have six letters. The total number of permutations of 6 letters = 6!

How many arrangements are there of the letters in BANANA such that the letter B is followed by an A '?

The answer is 46,080.