Latest TCS Aptitude Question SOLUTION: 18) A king’s durbar consists of a knight, a spy & a knave. knight speaks only truth, spy can speak either a truth or a lie & the knave speaks only lies. From the following statem

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18) A king’s durbar consists of a knight, a spy & a knave. knight speaks only truth, spy can speak either a truth or a lie & the knave speaks only lies. From the following statements made by 3 people A, B & C comprising knight, spy & knave not in same order. Identify the spy.
A Said “I am knight”.
B Said “A is not knave”.
C Said “If you had a asked me, I would say A is the spy”.

Asked In TCS snigdha (11 years ago)

Unsolved Read Solution (9)

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Read Solution (9) :

Denis  (11 years ago)

Assume A is KNIGHT , B says A is not KNAVE which is also right so B is SPY and C is naturally KNAVE and he gives a false statement.
Now assume B is KNIGHT , A cud b either SPY or KNAVE but if he is a spy then the statement of C who wud be KNAVE is true which is not possible so A has to b KNAVE which makes C the SPY but again the truthful KNIGHT says A is not KNAVE so this condition not true either.
Again assume C is the KNIGHT and he says A is the SPY which makes B the KNAVE and he says A is not KNAVE which is true thus contradicting his natural talent to lie so this condition is also not possible
Thus we do have an answer for this question which is B

Is this solution Helpfull? Yes (27) | No (1)  

Anjali Kaushik  (11 years ago)

knight-C
spy -A
knavea-B

Is this solution Helpfull? Yes (3) | No (11)  

jevita agarwal  (11 years ago)

a spy can be B bcoz
1st suppose A is telling the truth thn A-knight(bcoz knight speaks truth),nw B is saying A is not a knave thn he is also telling the truth(n it can be spy bcoz spy can either lie or saying the truth),thn C is saying that A is a spy nd it is nt true(so C is knave)

Is this solution Helpfull? Yes (3) | No   

BALENDU NARAIN PANDEY  (11 years ago)

A=Knight B= spy C =knave ... knight always sy truth so if A is knight so inorder to make A knight B has to be spy so that B tells truth about A that he is not knave ans then c would definately be knave

Is this solution Helpfull? Yes (3) | No (1)  

lakshmi bhargavi  (11 years ago)

this is dummy question... in tcs and no solution for this question

Is this solution Helpfull? Yes (2) | No (12)  

Kamlesh Ranjan  (9 years ago)

no solution possible

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

ramya  (8 years ago)

Assume the condition:
case (i) :
A=Knight
then, B's statement is right that "A is not knave"
obviously B vl b d SPY and C will b the KNAVE.
case (ii)
B=KNIGHT
then he says " A is not knave"..so A becomes spy and C d knave
but note c says A is d spy...if he s d knave he cant speak truth...therefore this condition is impossible.
case (iii)
C= KNIGHT
he says " A is the spy "
so A will b spy and B will be knave
but note b's statement...what he said was true..tat A is not knave...so B cant be knave (bcoz knave lie)
this condition is impossible.

therefore the spy will be "B"

Is this solution Helpfull? Yes (1) | No   

priyanshu saxena  (11 years ago)

anjali kindly explain the logic

Is this solution Helpfull? Yes | No (1)  

shivam  (11 years ago)

i have an answer for u all buddies
taking A as spy and he is telling lie
acc to this C will be knight as he always say truth and lier is knave i.e B

Is this solution Helpfull? Yes | No (3)  

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