THE OFFCICAL CAT2008: DI - lOGICAL REASOING

[prerna mathur]

Originally Posted by teenvan

Q: A,B,C,D,E are 5 persons speak the truth to only two of the other persons and lies to the other two.If A speaks the truth to one of (B,C) and one of (D,E);B speaks the truth to one of (C,D) and one of (A,E); C speaks the truth to one of (A,B) and one of (D,E).
If one person speaks the to another person , then this person also speaks the truth to the first person(i.e between a pair of person, they either speak the truth to each other or lie to each other.

1. If A speaks the truth to B,then E must speak the truth to?
2. If A speaks the truth to C,then both the person to whom a given person speaks the truth can be uniquely identified if the given person is
a. B b. D c. E d. both (a) or (b) e. both (a) or (c)

ques1) from d data provided we can c..
AB - T
AC - L
BC - T
BD - L
BE - L
now for d remainin give T or L to any one of them.. u'll get two arrangements (one with T and other with L)
if i give T or L to say CD then,
case I) case II)
CD - T CD - L
CE - L CE - T
AD - L AD - T
AE - T AE - L
DE - T DE - T
hence E always speaks d truth to D

ques 2) if A speaks d truth to C then we can figure out T or L for person B
BA - L
BC - L
BD - T
BE - T
hence ans a) B

[arbit_rageur]

Guys, try this( cross posting from the quant thread)

Eight players( A to H) took part in a chess tournament in which each player plays the other once.There are no draws in the tournament.The winner of the toournament is the one with maximum point and if two players ended up with the same number of max points, both are declared winners.It is known that C beat every player who beat D, and D beat every player who beat C. Further,None of the 8 players won all their matches. How many points did the winner(s) score? ( wins are awarded 1 point, losses no points)

1. A and B were declared the 2 joint winners of the tournament.
2. C scored exactly one point.

Choices( the usual choices)

a. Using 1 alone but not 2 alone
b. uSing 2 alone but not 1 alone
c. Using either statement alone
d. Using both together but not with either statement alone
e. Cannot be answered even by using both statemtns together.

[pawanjain19]

Is this thread active? Will you be posting the answer to this ques? i.e., should I even spend time on it?

Originally Posted by arbit_rageur

Guys, try this( cross posting from the quant thread)

Eight players( A to H) took part in a chess tournament in which each player plays the other once.There are no draws in the tournament.The winner of the toournament is the one with maximum point and if two players ended up with the same number of max points, both are declared winners.It is known that C beat every player who beat D, and D beat every player who beat C. Further,None of the 8 players won all their matches. How many points did the winner(s) score? ( wins are awarded 1 point, losses no points)

1. A and B were declared the 2 joint winners of the tournament.
2. C scored exactly one point.

Choices( the usual choices)

a. Using 1 alone but not 2 alone
b. uSing 2 alone but not 1 alone
c. Using either statement alone
d. Using both together but not with either statement alone
e. Cannot be answered even by using both statemtns together.

[shashank3012]

Originally Posted by arbit_rageur

Guys, try this( cross posting from the quant thread)

Eight players( A to H) took part in a chess tournament in which each player plays the other once.There are no draws in the tournament.The winner of the toournament is the one with maximum point and if two players ended up with the same number of max points, both are declared winners.It is known that C beat every player who beat D, and D beat every player who beat C. Further,None of the 8 players won all their matches. How many points did the winner(s) score? ( wins are awarded 1 point, losses no points)

1. A and B were declared the 2 joint winners of the tournament.
2. C scored exactly one point.

Choices( the usual choices)

a. Using 1 alone but not 2 alone
b. uSing 2 alone but not 1 alone
c. Using either statement alone
d. Using both together but not with either statement alone
e. Cannot be answered even by using both statemtns together.

statement 2:c scored i point=>he beat 1 player,the one who beat d or some other player,and d won all his matches.
so,d's final score would be 6.so,points earned by winner is 6.
statement 2 is sufficient by itself.

statement 1:a and b were joint winners.
so,they must have won at the most 5 matches.
they cannot win 4 matches each,as then,another player will be needed,who wins 4 or more than 4 matches.
so,winner has 5 points.
statement 1 is sufficient by itself too

my answer option(c)

[arbit_rageur]

Your answer is right.

Just to complete your explanation:

C and D together must have won atleast 7 matches as C beat all who beat D and D beat all who beat C. Effectively, every other player lost to either C or to D.

So statement 2 alone is enough.

A and B could have won either 6 or 5 matches if they are joint winners.But 6 is not possible because one of A and B lost to the other and each lost to one of C or D, so atleast one of A and B must score 5 points or lesser.

implies both scred 5 points.

So Statement 1 alone is enough.

So Answer is C).

Originally Posted by shashank3012

statement 2:c scored i point=>he beat 1 player,the one who beat d or some other player,and d won all his matches.
so,d's final score would be 6.so,points earned by winner is 6.
statement 2 is sufficient by itself.

statement 1:a and b were joint winners.
so,they must have won at the most 5 matches.
they cannot win 4 matches each,as then,another player will be needed,who wins 4 or more than 4 matches.
so,winner has 5 points.
statement 1 is sufficient by itself too

my answer option(c)