Logic Quiz

Southie · July 30, 2015, 1:57am

Re: Logic Quiz

The problems statement was there were 100 blue eyed people and one guru who is green eyed. That statement was incorrect based on solution offered.

psyah · July 30, 2015, 4:59am

Re: Logic Quiz

MustafaQuraishi:

Alright guys … I guess its time to explain. couple of guys almost had the correct answer though their explanation wasn’t “logical”. I will update this post after sometime to list those name who had the correct answer.

now lets talk about the answer.

You can related these questions to mathematical induction in which you need to prove it for k and then k+1 … and the rest is proven automatically. In pure CS terms, you need to break down this problem to 3 boundaries.

What if there is no blue eye people

What if there is one blue eye people
2.a what if there are two blue eye people

based on 2, and 2.a you can deduce what if there are N blue eye people

**
Case 1

**What if there is no blue eye people, so the guru says “I don’t see any blue eye” … kahani khatm!

Case 2
What if there is one blue eye person. The guru says, “she see at least 1 blue eye person”. Now the blue eye person can see rest of the 99 people and all of them are brown eyes. Given that Guru sees one blue eye, he can logically deduce that he is the one Guru is talking about. So he leaves at first night (number of blue eye people = 1 … he left at 1 night)

**Case 2.a
**What if there are two blue eye person. The guru says, “she see at least 1 blue eye people”. Now the first blue eye person see that there are 98 brown eye , 1 blue and and then him. He assumes, that the blue eye person would leave tonight (see Case 2). Same goes for the other blue eye person, he would assume that the first blue eye would leave tonight (see case 2) but both of them didn’t. Which leads them to logically deduce that they see “another” blue eye person and they want to make sure. On the second day, the guru says the same thing (this is almost useless here) … But tonight they can make the decision since they know the other blue eyed person didn’t leave, so it must be him which is also blue eye. So both of them would leave on night 2. (number of blue eye people = 2 … they left at 2 night)

**Case 3
**From case 2 and 2.a you can deduce that given that there are N blue eye people at the island, they will leave at Nth night which would be 100 in this case.

Brother if you had explained that she announces every day at noon then I would have arrived at this solution. I avoided answering in that way because that detail was not provided.

And this solution is quite easy if that piece of information was made more clear.

Southie · July 30, 2015, 5:47am

Re: Logic Quiz

Are we going to get our money back?

psyah · July 30, 2015, 6:42am

Re: Logic Quiz

I have made up a math problem:

A <> B
AB = C
C < 100
A/B = X
X is a PRIME INTEGER

At this point …
B is such that there are exactly 2 possible A values.

Given that CX > 100

Solve: Value of A and B?

Eastern_Dresses · July 30, 2015, 8:24am

Re: Logic Quiz

Can you explain this A <> B

HKHamzaKhan93 · July 30, 2015, 8:51am

Re: Logic Quiz

I suppose it’s the *greater than or equal to *sign.

Restored attachments:

psyah · July 30, 2015, 10:32am

Re: Logic Quiz

^ It means “not equal to”

HKHamzaKhan93 · July 30, 2015, 10:41am

Re: Logic Quiz

Means..

Restored attachments:

psyah · July 30, 2015, 10:46am

Re: Logic Quiz

Yes this symbol you posted and <> symbol that I posted mean the same thing …

Not equaledit]

The symbol used to denote inequation (when items are not equal) is a slashed equals sign “≠” (U+2260; 2260,Alt+X in Microsoft Windows). In LaTeX, this is done with the "
eq" command.
Most programming languages, limiting themselves to the ASCII character set and typeable characters, use ~=, !=, /=, =/=, or <> to represent their Boolean inequality operator.

OYMWA · July 30, 2015, 3:21pm

Re: Logic Quiz

Assuming, they are integers,

A=10, B=5

bitter · July 30, 2015, 3:23pm

Re: Logic Quiz

12.5 is not a prime integer!

psyah · July 30, 2015, 3:25pm

Re: Logic Quiz

Yes please take A and B as integers.

bitter · July 30, 2015, 3:26pm

Re: Logic Quiz

The nos can be

A 22
B 2

SID_NY · July 30, 2015, 3:27pm

Re: Logic Quiz

Wut does it mean by..

??

psyah · July 30, 2015, 3:37pm

Re: Logic Quiz

Peace SID_NY

Yes that is my British efficiency coming out … It means that out of all the possible value combinations of A and B you can eliminate any of the combinations where the same number for B appears either once or more than two times. This will give only two possible combinations and the correct one will be where CX > 100.

OYMWA · July 30, 2015, 3:37pm

Re: Logic Quiz

Yes you are right. Picked the wrong factors, should be 10 and 5. Still have another issue though. CX = 100 and not CX > 100.

SID_NY · July 30, 2015, 3:44pm

Re: Logic Quiz

Still confused.. any examples?

psyah · July 30, 2015, 5:16pm

Re: Logic Quiz

In the answer there two possible A values for two possible B values that satisfy the above …

coming back to SIDs question …

let’s say you have got the following list as an answer to a different question.

4, 5
5, 5
6, 3
8, 3
11, 1
9, 2
8, 2
7, 2

In this list for the given values of B there two combinations for B= 5, two combinations for B = 3, one combination for B = 1, and three combinations for B = 2 … So only those combinations are valid where there are two combinations for B no less and no more. So we can eliminate B = 1 and B = 2 … Leaving us with 4 combinations that are valid, which are the top 4 in this list.

psyah · July 30, 2015, 5:21pm

Re: Logic Quiz

here
if A is 14 then B is 2, or if A is 34, and B is 2 , we already have 3 combinations where B = 2 … Which means B cannot be 2. The rules say the possible combinations that use the same value for B must be two.

MustafaQuraishi · July 30, 2015, 6:02pm

Re: Logic Quiz

doesn’t look like i can solve it on computer. Gotta sit down with pen and paper.

I will be back …