In a group of children each child gives a gift to every other. If the number of gifts is 132, find t

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24 Aug 2013 In a group

In a group of children each child gives a gift to every other. If the number of gifts is 132, find the number of children.

OPtion

1) 11
2) 12
3) 14
4) 16
5) 18
6) 22
7) 24
8) 28
9) 32
10) None of these

Solution

Let there are n children, then each child will have n-1 gifts.
Total number of gift=total number of children*number of gifts per child
n(n-1)=132
solve
n can not be -ve
n=12

option 2

Correct Option: 2 Best Solution (20)

devendra kumar gond   11 years AGO

Let there are N children,then each of them will give (N-1) gifts,(each children will not gift himself)
Total gifts =N*(N-1) =N^2 -N
N^2 -N =132
N^2 -N -132 =0
(N-12)(N+11) =0
N = 12 ,-11
as number of children can not be negative,
so number of children =12

Like? Yes (22) | No (6)  

Dr.Dipin Singh   11 years AGO

If there are n chidren, then each gave (n-1)gifts.
so n(n-1)=132=12*11
so n=12

Like? Yes (20) | No (4)  

Anu   11 years AGO

assume that there are n children and the number of gifts will be defined as n-1 as each child gives a gift to every other.
clearly n(n-1)=132
n^2-n-132=0
(n-12)(n+11)=0
n=12 is taken as it is positive!!!
therefore the answer is 12.

Like? Yes (20) | No (6)  

Chandni Maurya   11 years AGO

ans=(2). 12
let x be the no of children,
x(x-1)=132
=>x^2-x-132=0
=>(x-12)(x+11)=0
=> x=12,-11 => x=12

Like? Yes (12) | No (1)  

SOMASHEKAR MACHANI   11 years AGO

x(x-1) = 132
solve for x ....
we get x = 12

Like? Yes (15) | No (4)  

sudipta sadhukhan   11 years AGO

say their are n members in the group.
so, their are (n-1)options to each of them,so that the child can give gifts to other (n-1)members.
So the result will be n*(n-1).
here n*(n-1)=132 =>n=12

Like? Yes (9) | No   

Mehak Koul   11 years AGO

each child will give 1 gift less than the total no of children in a group. so if there are 12 children in a group each will give 11 gifts. toatl becomes 12*11=132 gifts.

Like? Yes (7) | No (2)  

Devendra Marghade   11 years AGO

If n=number of children &
if each child gives a gift to every other,then total number of gifts=n*(n-1)=132 or
n^2-n-132=0 ,(n-12)(n+11)=0, n=12

Like? Yes (7) | No (3)  

T Lokesh   11 years AGO

each children gives a gift to other children
hence no of gits when n children are present =n*(n-1)
so n*(n-1)=132
by solving we get n=12 and n=-11
n cant be a negative number
so no of students =12

Like? Yes (6) | No (3)  

praveen sb   11 years AGO

let there be X students .. if each student gives a gift to everyone it means one student gives gift to X-1 students ... therefore X(X-1)=132
by solving we get X=12

Like? Yes (5) | No (2)  

krishnapriya   11 years AGO

Let the no. of children be 'n'
Each child gives a gift to others.
n(n-1)=132
n^2-n-132=0
so, n=12

Like? Yes (5) | No (3)  

Abhishek   11 years AGO

Suppose we have n children in the group, so each child will give gifts to every other child and so the required gifts will be n*(n-1).
n*(n-1) = 132
As we have total 132 gifts available.
After solving we get 12.
So there must be 12 children in the group.

Like? Yes (4) | No (2)  

Neeraj Kumar   11 years AGO

Let the number of the children be x.
Since every children gives gift to all remaining children therefore every children will produce x-1 gifts.
Hence total number of gifts = x(x-1)
that is x(x-1) = 132=12*11
gives x= 12
Hence number of children is 12.
Option 2 is correct.

Like? Yes (4) | No (2)  

Shikha Sinha   11 years AGO

let no of children be n.... now if we find permutation i.e nP2=132... on finding n... it gives no of children.

Like? Yes (4) | No (4)  

manasa epuru   11 years AGO

n(n-1)=132=12*11
no of students=12

Like? Yes (3) | No (3)  

Ananya Gupta   11 years AGO

let the no. of children be n.
each child gives (n-1) gifts to everyone except himself.
then
n*(n-1)=132
we get n=-11,12
so 12 is the correct answer.

Like? Yes (2) | No (3)  

Vinay Sipani    11 years AGO

nP2 = 132
n(n-1) = 132
n = 12

Like? Yes (4) | No (6)  

Susmit Bansod   11 years AGO

if there are x students in a group, each student will give (x-1) gifts. so, total gifts are x(x-1). therefore,x(x-1)=132. so, x=12

Like? Yes (1) | No (3)  

rohit punekar   11 years AGO

if the nomber of children are 12 then,
each child gives one gift to the other 11 childrens.
therefore,12*11=132
hence,the answer is 12.

Like? Yes (2) | No (4)  

vky   11 years AGO

{(n-1)*n}/2=132
n=12
since one will gift to (n-1) children and then (n-2) and so on.
so (n-1)+(n-2)+......+3+2+1={(n-1)*n}/2

Like? Yes (2) | No (5)