Latest Microsoft Aptitude Question SOLUTION: There are N number of detectives , each one knows an information, how many calls should they make so all the detectives know all the N number of info. ?

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There are N number of detectives , each one knows an information, how many calls should they make so all the detectives know all the N number of info. ?

Asked In Microsoft Banumathy (10 years ago)

Unsolved Read Solution (33)

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Read Solution (33) :

dhanesh  (10 years ago)

sorry the solution is ---> N(N-1)/2

Is this solution Helpfull? Yes (19) | No (4)  

Roshan jha  (10 years ago)

(n-1)+(n-2). !st one will call the 2nd and give information and take information. Then he will call the 3rd and will give the information of his and 2nd detective to him. this process continues till n-1 detective. Now he has information of all the detective. So he will call all other n-2 detective(except him and last one who already has all the information) and will give the information to all.
so total call=(n-1)+(n-2)

Is this solution Helpfull? Yes (16) | No (3)  

srikanth reddy  (10 years ago)

each one makes n-1 calls , so ans is n*n-1

Is this solution Helpfull? Yes (9) | No (6)  

k a n v v v prasad  (10 years ago)

(n-1) ways

Is this solution Helpfull? Yes (3) | No (6)  

Amit Chaurasia  (10 years ago)

The answer is (n-1)+(n-2)+...+1=(n(n-1))/2.
First caller needs to make n-1 calls,
Second caller needs to make n-2 calls since he knows the secret of the first caller and so on...

Is this solution Helpfull? Yes (3) | No   

Hitansu  (10 years ago)

Total Calls = C(N,2)= [N(N-1)]/2

Explanation:
1 call needed to share information between each of two detectives.
If there are N detectives., it need C(N 2) combinations.

Is this solution Helpfull? Yes (2) | No (1)  

srikanth reddy  (10 years ago)

sorry the answer is n-1! i.e n-1 factorial....

Is this solution Helpfull? Yes (2) | No (3)  

Shivam Gandhi   (10 years ago)

1st detective calls n-1 other detectives and gives them the information of all the detectives whom he has called just before calling a particular one.

So, at the end of 1st cycle, 1st detective and last detective both will have N number of info. Detective n-1 will have n-1 info. Detective n-2 will have n-2 info and so on. 2nd detective will have 2 info.

Now, another cycle starts in which nth detective calls detectives 2-(n-1) giving them info. of all the previously called detectives (same as in 1st cycle).

Thus, at the end of this cycle, all the detectives will have N no. of info.

So, total no. of calls =(N-1) + (N-2) = 2*N-3

Is this solution Helpfull? Yes (2) | No (1)  

Arun Karthick  (9 years ago)

(n-1)+(n-2)=2n-3

Is this solution Helpfull? Yes (2) | No   

Bholanath   (10 years ago)

answer is
nC2...

Is this solution Helpfull? Yes (1) | No (2)  

krishna yadav  (10 years ago)

nth det. has to make n-1 calls
(n-1)th .... ..... ..... n-2 calls
.
.
1st...........1 call
total no of call=(n-1)+(n-2)+...+1
=>(n-1)(n-2)/2

Is this solution Helpfull? Yes (1) | No   

radhe shyam  (10 years ago)

selecting 2 out of n = nC2=n(n-1)/2

Is this solution Helpfull? Yes (1) | No   

shashank  (10 years ago)

(n-1) ways

Is this solution Helpfull? Yes (1) | No   

D.Sri Tejaswini  (9 years ago)

the answer is n(n-1)/2

Is this solution Helpfull? Yes (1) | No   

Asha  (9 years ago)

N-1:for gathering whole info

N-2:Share the all information

Total: (N-1)+(N-3)=2N-3

Is this solution Helpfull? Yes (1) | No   

ASHISH AGGARWAL  (10 years ago)

numCall=0
while(N!=1)
{
x += N/2;
N -= N/2;
}

Is this solution Helpfull? Yes | No (4)  

dhanesh  (10 years ago)

(N(N+1)/2)-1

Is this solution Helpfull? Yes | No   

Deblina Manna  (10 years ago)

see,each detective will call n-1 no of detectives to inform them about his information...so n detectives will make total n*(n-1) no of calls.

Is this solution Helpfull? Yes | No   

Kirtiwardhan Tandale  (10 years ago)

n(n-1) or nC2 * 2!

Is this solution Helpfull? Yes | No   

rajat  (10 years ago)

n-1 first one will call second..second will call third telling info of 1st one too..so each call next one..n-1 ways

Is this solution Helpfull? Yes | No   

Arup Banerjee  (10 years ago)

As there are n persons . each of them has to make n-1 calls to inform of his/her piece of information to others as he/she will exclude himself/herself for his/her information as he/she already knows it . so if there are 2 persons the number of calls to be made is 2*(n-1). And hence, for n number of persons it should be n*(n-1).

Is this solution Helpfull? Yes | No   

Sajib Ghosh  (10 years ago)

Each detective knows only one information.
so, there are n no. of information. so, they have to know n-1 more information. so, n-1 call is needed to know ALL the information of a single detective.. thre are n-1 more detectives so,, total no. of calls-->> n*(n-1)

Is this solution Helpfull? Yes | No   

anoop kumar  (10 years ago)

it is (n-1)! ways.

Is this solution Helpfull? Yes | No   

Aditya Pulekar  (10 years ago)

If in the given question we assume that the info sharing is happening two-way when a call is made then ans= [n*(n-1)]/2 ......but if the sharing of info is just one-way when a call is made then the ans= [n*(n-1)]

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santhi   (9 years ago)

N=information
N-1 call to share the all information.

Is this solution Helpfull? Yes | No   

Sumit Sharma  (9 years ago)

N-1
if suppose there are three detectives.one call the second and give him the information.now second calls third and give him the information of himself and the first detectives.on similar grounds it would take N-1 calls

Is this solution Helpfull? Yes | No   

souharda  (9 years ago)

N^2
each one will make n calls as the known info may be repeated

Is this solution Helpfull? Yes | No   

iman  (9 years ago)

1st detective calls N-1 others
then 2nd detective calls 1st one and can collect all the info.=1 call
so on for N-1 detectives
total calls= N-1+N-1 = 2N-2

Is this solution Helpfull? Yes | No   

Ishan Gautam  (9 years ago)

2(n-1)
1st detective will call 2nd one and share al his information then, 2nd detective will call 3rd one and he will share his information as well as information from 1st detective. And this process will continue till the nth detective obtain all the information. so till now there will be (n-1) calls
after that nth detective will call 1st detective to share all the information and then 1st one will call 2nd one and 2nd one will call the 3rd one and this process will continue till the (n-1)th detective obtain all the information. so here also (n-1) call were made.
so total calls made= (n-1) + (n-1)
= 2n-2= 2(n-1)

Is this solution Helpfull? Yes | No   

rahul anand  (9 years ago)

n*n-n
because each one will make to others all and we need to substract n because they will exchange of their own. so substract the n

Is this solution Helpfull? Yes | No   

ram  (9 years ago)

(n-1)!
lets say 4 detectives.
N1 -> N2
N1 -> N3
N1 -> N4

3 CALLS (N1) + 2 CALLS (NOW BY N2)+ 1 CALL (NOW BY N3) i.e. (n-1)!

Is this solution Helpfull? Yes | No   

ADITYA VEER VIKRAM SINGH  (6 years ago)

n/2(log n)
(1,2,3,4,5,6,7,8) =4
/
(1,2,3,4) (5,6,7,8) =4
/ /
(1,2) (3,4) (5,6) (7,8) =4
n/2 at each level. If any information is exchanged by any ditective then both will contain the union of information.

Is this solution Helpfull? Yes | No (1)  

Bhavana Gollapudi  (6 years ago)

one should make n-1 calls excluding him.For n members,the calls should be n*n-1

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