Meeting

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Meeting

by Aman verma » Mon Feb 22, 2010 6:03 am
Q : At a meeting of the Senate there were n people.As per the convention everyone has received some chocolates in the following manner . As A,B,C,D,E ...... etc have received 1,2,3,4,5....etc chocolates respectively.Before anyone has eaten a bit of chocolate, due to some urgent call , the chairman left the meeting with his chocolates . Later on the rest of the attendants collected their chocolates in a box and then redistributed all the chocolates evenly among themselves and thus everyone has received 13 chocolates .Minimum number of person who attended the meeting can be :

a) 15

b) 18

c) 24

d)32

e) 38



Ans [spoiler]c)24[/spoiler]
Last edited by Aman verma on Mon Feb 22, 2010 6:16 am, edited 1 time in total.
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by harsh.champ » Mon Feb 22, 2010 6:12 am
Aman verma wrote:Q : At a meeting of the Senate there were n people.As per the convention everyone has received some chocolates in the following manner . As A,B,C,D,E ...... etc have received 1,2,3,4,5....etc chocolates respectively.Before anyone has eaten a bit of chocolate, due to some urgent call , the chairman left the meeting with his chocolates . Later on the rest of the attendants collected their chocolates in a box and then redistributed all the chocolates evenly among themselves and thus everyone has received 13 chocolates .Minimum number of person who attended the meeting can be :

a) 15

b) 18

c) 24

d)32

e) 38



Ans 24
1+2+3+4+......+n = total no. of chocolates = n(n+1)/2
Now,for minimum no. of persons,the chairman should be the nth person.
Hence,n(n+1)/2 -n =13(n-1)
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by firdaus117 » Mon Feb 22, 2010 6:28 am
harsh.champ wrote:
1+2+3+4+......+n = total no. of chocolates = n(n+1)/2
Now,for minimum no. of persons,the chairman should be the nth person.
Hence,n(n+1)/2 -n =13(n-1)
Hey your solution yields no result.Check it urself.You have wrongly assumed that chairman has to be n th person for minimising 'n'.
I have an easier approach to this question i.e. work through options.
1. 15 sum=120 13*14=182 Rejected
2. 18 Sum=171 13* 17=221 Rejected
3. 24 Sum=300 13*23=299 Accepted
The chairman will have 300-299=1 chocolate. :)Poor man.What's the use being a chairman if u can't have all chocolates.

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by harsh.champ » Mon Feb 22, 2010 6:34 am
firdaus117 wrote:
harsh.champ wrote:
1+2+3+4+......+n = total no. of chocolates = n(n+1)/2
Now,for minimum no. of persons,the chairman should be the 1st person.
Hence,n(n+1)/2 -n =13(n-1)
Hey your solution yields no result.Check it urself.You have wrongly assumed that chairman has to be n th person for minimising 'n'.
I have an easier approach to this question i.e. work through options.
1. 15 sum=120 13*14=182 Rejected
2. 18 Sum=171 13* 17=221 Rejected
3. 24 Sum=300 13*23=299 Accepted
The chairman will have 300-299=1 chocolate. :)Poor man.What's the use being a chairman if u can't have all chocolates.
Hey firdaus,
Thanks .Great approach over here.
Actually,I took the other-way-round .
It should be
the chairman should be the 1st person.
Hence,answer is n(n+1)/2 -1 =13(n-1)
which is 24 C.
I guess now it is correct. :)
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by firdaus117 » Mon Feb 22, 2010 6:40 am
harsh.champ wrote:
firdaus117 wrote:
harsh.champ wrote:
1+2+3+4+......+n = total no. of chocolates = n(n+1)/2
Now,for minimum no. of persons,the chairman should be the 1st person.
Hence,n(n+1)/2 -n =13(n-1)
Hey your solution yields no result.Check it urself.You have wrongly assumed that chairman has to be n th person for minimising 'n'.
I have an easier approach to this question i.e. work through options.
1. 15 sum=120 13*14=182 Rejected
2. 18 Sum=171 13* 17=221 Rejected
3. 24 Sum=300 13*23=299 Accepted
The chairman will have 300-299=1 chocolate. :)Poor man.What's the use being a chairman if u can't have all chocolates.
Hey firdaus,
Thanks .Great approach over here.
Actually,I took the other-way-round .
It should be
the chairman should be the 1st person.
Hence,answer is n(n+1)/2 -1 =13(n-1)
which is 24 C.
I guess now it is correct. :)
Hmm still not correct.How would you know beforehand that he has one chocolate.
However,if you still insist on doing it conventionally,then take an arbitrary value
n(n+1)/2 - k = 13(n-1) with condition k<=n
U will get a quadratic equation of 'n'.Take the condition as for integral 'n',the determinant will be a perfect square. :)

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by Aman verma » Mon Feb 22, 2010 11:23 am
In the above question , maximum how many chocolates were there to be received by all of them,initially :

a)300

b)351

c)450

d)551

e)650

Ans [spoiler]b)351[/spoiler]

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by Aman verma » Tue Feb 23, 2010 3:42 am
Hey folks, I got no solution from anybody on the second part of the question ?
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by harsh.champ » Tue Feb 23, 2010 4:42 am
Aman verma wrote:Hey folks, I got no solution from anybody on the second part of the question ?
Refer to the 1st post I made:-
subtract n from the sum of n natural no.s
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by firdaus117 » Tue Feb 23, 2010 6:33 am
Aman verma wrote:Hey folks, I got no solution from anybody on the second part of the question ?
Oh,I missed the second question.But probably if you had posted it in a new thread,you would have elicited prompt response.
As it is required to calculate maximum number of chocolates,it would mean that the chairman had 'n' number of chocolates before he left:
So,total chocolates with members earlier were 13(n-1)+n=14n-13
Now work through options,start from highest value(why?)
Option 5.650
14n-13=650
0r,n=673/14 not an integer Rejected
Option 4.551
14n-13=551
or, n=564/14 Rejected
Option 3.450 Rejected on similar logic
Option 2.351
n=26 An integer Accepted :D