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Ask community Community Discussion Question: Contest [swordfish #3]: Find ways to distribute identical balls in identical boxes
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uday_sravan (5)

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The total no. of ways in which 30 balls can be distributed among 3 boxes is 30+3-1C3-1=496.
 No. of ways any of the boxes can get zero no. of balls is 6.
 
So, the required answer is 496-6=490
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10904him (114)

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No of ways is = 28 x 28 x 28 Ans.
                    

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Titun (1467)

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First, let us put one ball in each of the 3 boxes. So, now no box remains empty & we have to just distribute 27 balls in 3 identical boxes.
 
The no. of ways by which this can be done = (The no. of non-negative integral solutions of the eqn. a + b + c = 27 ) = [(3+ 27-1)C27]/3 = 29C27 = 406
 
Here, I have made an assumption that the case when x no. of balls are in the 1st box, y no. of ball are in the 2nd box and the remaining balls in the 3rd box & the case when y no. of balls are in the 1st box, x no. of ball are in the 2nd box and the remaining balls in the 3rd box are distict cases and both of them are taken into account.
 
Strictly speaking, these two are not distinct cases as the boxes are identical.
 
So, actual no. of cases = 406/3
But since this is not an integer, I have made the above assumption.

You never know what is enough till you know what is more than enough.

Titun
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Das Mukerjee (9)

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The reqd. no. of ways = no. of positive integral solutions of
p+q+r = 30
 
Let p = m + 1, q = n + 1, r = k + 1
Therefore, m+n+k = 27
Hence, no. of integral solns of m+n+k=27 is 29C2
But since the boxes are identical, total no. of ways = (29C2)/3

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ijaz17 (0)

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30x29x28
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preksha madan (15)

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for each box minimum no of balls that shud b kept is 1 n maximum is27......
after that..
if we go in decending order ...did any1 noticed a pattern....
if we take 27 in any of the identical box then case formed is...
27 , 0 , 0.......it has jus' got a single case
again with 26 in any of the identical box .....
26 , 1 ,0...... it too has got 1 case...
but if we go on in decending order...
we find after every 2 consecutive cases....that the no. of casas increases....
i.e.for 27 n 26 we have 1 case each
for 25 n 24 we have 2 cases each
for 23 n 22 we have 3 cases each
...n so on...........

life isn't about waitin' 4 the storm 2 pass by , it's 'bout dancing in rains............
preksha_madan@yahoo.co.in


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trachion_me (0)

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i got it in two ways:-1)1ball should be there in each compulsorily so rem are 27 balls & 3boxes
    so no of ways =27+3c27 =29*28/2=406ways
 
 
2) partition method
        11111111111111111111111111100 no of arrangements
= 29!/27!2! =406 ways
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chandrasekhar (12)

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swordfish #3 result I'm afraid, no student has been able to answer this question with the correct technique.
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rachitaw (0)

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TOTAL NO. OF BALLS=30
TOTAL NO. OF BAOXES = 3
SINCE EACH BALL CAN BE PUT IN ANY OF THE THREE BOXES. SO, THE TOTAL NO. WAYS IN WHICH 30 BALLS CAN BE PUT IN 3 BOXES= 330
                                                                                                                                   
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10904him (114)

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Let 1 ball be placed in each box then the no of balls left=27
Now these 27 balls can be distributed in the three boxes in the
following no of ways=27C3

Being a genius is 1% luck and 99% perspiration........
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10904him (114)

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Sorry I made a mistake
Total=27C3+27C2 + 27C1

Being a genius is 1% luck and 99% perspiration........
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zuberahmed (32)

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I agree with NIKUNJ_94's answer
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gorakavipraveen (118)

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CHANDRASEKHAR sir, isnt it 27. I am pretty sure with it till now. Please disclose the answere. I know that every box can be filled with 1 to 27 balls and no matter what it is or which box it is as they all aer identical. so I guessed 27.
Am I wrong? Atlest email me sir.

Praveen kumar gorakavi
Hyderabad.
gorakavipraveen@gmail.com
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CyBorG (1574)

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The answer is 30-1C3-1=29C2=406
 

-ADARSH
NITK Surathkal

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tejasvi2389 (33)

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First give 1ball to each box
The remaining 27 balls can be distributed in the 3 boxes in 27C3 ways
Therefore required no. of ways is 1X27C3=27C3
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vaibhavbright (247)

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The correct ans is definitely
 
         105

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gorakavipraveen (118)

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vaibhavbright but how an you be so confident, whats you solouition man!!!!!!!!!!

Praveen kumar gorakavi
Hyderabad.
gorakavipraveen@gmail.com
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preksha madan (15)

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first let us find out no. of ways of destributing 30 identical balls in 3 different box...(X Y Z)

(27+3-1) C (3-1)
=(29) C (2)
=406 cases

X+Y+Z=27.

(((.note..... X !=Y meansXis not equal to Y)))

IN THIS WE HAVE 3 CASES...
(1) when X=Y=Z.......it will hav only 1 case.....(a)
(2) when X !=Y=z....&....X=Y!=Z......&...X=Z!=Y....
it has....
(1,1,25)
(2,2,23)
...
..
..
&so on till (13,13,1)....
i.e. 13 cases...
&we have 3 such identical boxes......
therefore we have 13 * 3 = 39 cases.......(b)

(3)when X !=Y!=Z
it has( total no. of ways - cases in which atleast 2 are equal)
i.e. 406 -40
=366.....(c)
as we have identical balls therefore we are considering the same cases 6 times ....therefore we will devide...
366 / 6 = 61......(d)
therefore total no of ways are (a)+(b)+(d)...
i.e.1+13+61 = 75......
therefore answere is 75......

life isn't about waitin' 4 the storm 2 pass by , it's 'bout dancing in rains............
preksha_madan@yahoo.co.in


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preksha madan (15)

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first let us find out no. of ways of destributing 30 identical balls in 3 different box...(X Y Z)

(27+3-1) C (3-1)
=(29) C (2)
=406 cases

X+Y+Z=27.

(((.note..... X !=Y meansXis not equal to Y)))

IN THIS WE HAVE 3 CASES...
(1) when X=Y=Z.......it will hav only 1 case.....(a)
(2) when X !=Y=z....&....X=Y!=Z......&...X=Z!=Y....
it has....
(1,1,25)
(2,2,23)
...
..
..
&so on till (13,13,1)....
i.e. 13 cases...
&we have 3 such identical boxes......
therefore we have 13 * 3 = 39 cases.......(b)

(3)when X !=Y!=Z
it has( total no. of ways - cases in which atleast 2 are equal)
i.e. 406 -40
=366.....(c)
as we have identical balls therefore we are considering the same cases 6 times ....therefore we will devide...
366 / 6 = 61......(d)
therefore total no of ways are
i.e.1+13+61 = 75......
therefore answere is 75......

life isn't about waitin' 4 the storm 2 pass by , it's 'bout dancing in rains............
preksha_madan@yahoo.co.in


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preksha madan (15)

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n i would like 2 know ur answer vaibhav....

life isn't about waitin' 4 the storm 2 pass by , it's 'bout dancing in rains............
preksha_madan@yahoo.co.in


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