Question:1
Six persons- A,B,C,D,E and F sit around a circular table.Is the person opposite to D adjacent to the person Opposite to F?
1.) B is towards the right of D and F is to the left of E.
2.) F is in Between C and A.
Answer with Proper explanations
Brain Teasers
This topic has expert replies
- gmat740
- MBA Student
- Posts: 1194
- Joined: Sat Aug 16, 2008 9:42 pm
- Location: Paris, France
- Thanked: 71 times
- Followed by:17 members
- GMAT Score:710
Question 2.
The students of a class are standing in a row all facing North.How many students are between Adam and Bryan?
1.) The number of students towards the left of Adam is 15 and Bryan is 10th from the right end.
2.) One third of the total number of students are in between Adam and Bryan.
Answer with proper Question Number and explanations.
The students of a class are standing in a row all facing North.How many students are between Adam and Bryan?
1.) The number of students towards the left of Adam is 15 and Bryan is 10th from the right end.
2.) One third of the total number of students are in between Adam and Bryan.
Answer with proper Question Number and explanations.
-
- Legendary Member
- Posts: 2467
- Joined: Thu Aug 28, 2008 6:14 pm
- Thanked: 331 times
- Followed by:11 members
Q 2.
Stmt I
The number of students towards the left of Adam is 15 and Bryan is 10th from the right end
15 BRYAN ADAM 9 - >one possible combination (0 people between)
6 brian 8 adam -> 8 people
INSUFF
Stmt II
One third of the total number of students are in between Adam and Bryan
No idea on what the total number of students are
Together:
total = 18
8 BRIAN 6 ADAM 2
C
Hope I am not missing something or another combination/total
Stmt I
The number of students towards the left of Adam is 15 and Bryan is 10th from the right end
15 BRYAN ADAM 9 - >one possible combination (0 people between)
6 brian 8 adam -> 8 people
INSUFF
Stmt II
One third of the total number of students are in between Adam and Bryan
No idea on what the total number of students are
Together:
total = 18
8 BRIAN 6 ADAM 2
C
Hope I am not missing something or another combination/total
-
- Master | Next Rank: 500 Posts
- Posts: 107
- Joined: Wed Mar 04, 2009 4:39 am
- Location: Vancouver
- Thanked: 9 times
- GMAT Score:750
Answer is E.
For me the only way to solve it is to draw out the possibilities. And it's time consuming. If anybody knows a better way, please share.
Draw a circle as the table. Clockwise mark 1,2,3,4,5,6 evenly spaced spots, as the seats for 6 people.
From the question stem, we know that if we want to meet the requirements, D and F must be adjacent. (Their sequence doesn't matter for now). I put D at seat 1. So F must be at seat 2 or 6.
On the other hand, if we place F at 3, 4 or 5, and still meet conditions in stmt 1 or 2, it means it's insufficient.
Stmt 1
I put F on seat 5, B on seat 6 (toward right of D), E on seat 4 (so F is on its left). This arrangement meets condition in stmt 1, but not the condition in question stem. Insufficient.
Stmt 2
I put F on seat 4, B on seat 6, E on seat 2. C and A are on seat 3 and 5. Now this arrangement meets conditions both in stmt 2 and stmt 1. But it still doesn't meet question stem condition. Insufficient.
Answer is E.
For me the only way to solve it is to draw out the possibilities. And it's time consuming. If anybody knows a better way, please share.
Draw a circle as the table. Clockwise mark 1,2,3,4,5,6 evenly spaced spots, as the seats for 6 people.
From the question stem, we know that if we want to meet the requirements, D and F must be adjacent. (Their sequence doesn't matter for now). I put D at seat 1. So F must be at seat 2 or 6.
On the other hand, if we place F at 3, 4 or 5, and still meet conditions in stmt 1 or 2, it means it's insufficient.
Stmt 1
I put F on seat 5, B on seat 6 (toward right of D), E on seat 4 (so F is on its left). This arrangement meets condition in stmt 1, but not the condition in question stem. Insufficient.
Stmt 2
I put F on seat 4, B on seat 6, E on seat 2. C and A are on seat 3 and 5. Now this arrangement meets conditions both in stmt 2 and stmt 1. But it still doesn't meet question stem condition. Insufficient.
Answer is E.
Six persons- A,B,C,D,E and F sit around a circular table.Is the person opposite to D adjacent to the person Opposite to F?
1.) B is towards the right of D and F is to the left of E.
2.) F is in Between C and A.
---
I think the answer is C
From Stmt I, we know that B sit towards the right of D, and F is to the left of E. But we don't know whether F sit near D or opposite to B ( it can't sit near B because to the left of F is E ) => INSUFF
From Stmt II, we know that F between C & A, but we don't know about others. It could be ... C F A ... or .... A ? F ? C .... so we can't answer the question
Combine I & II
now we know that F can't sit near D or B, near D or B must be ether C or A. And we know that on the right of F is two persons: E and C or A. We wil have something like this
= D = B =
A = = = C
= F = E =
So D is actually opposite to F, and we can say no to the question.
That's why I choose C.
Just my 2c
1.) B is towards the right of D and F is to the left of E.
2.) F is in Between C and A.
---
I think the answer is C
From Stmt I, we know that B sit towards the right of D, and F is to the left of E. But we don't know whether F sit near D or opposite to B ( it can't sit near B because to the left of F is E ) => INSUFF
From Stmt II, we know that F between C & A, but we don't know about others. It could be ... C F A ... or .... A ? F ? C .... so we can't answer the question
Combine I & II
now we know that F can't sit near D or B, near D or B must be ether C or A. And we know that on the right of F is two persons: E and C or A. We wil have something like this
= D = B =
A = = = C
= F = E =
So D is actually opposite to F, and we can say no to the question.
That's why I choose C.
Just my 2c
-
- Master | Next Rank: 500 Posts
- Posts: 107
- Joined: Wed Mar 04, 2009 4:39 am
- Location: Vancouver
- Thanked: 9 times
- GMAT Score:750
Hi quocbao,
For this arrangement (thanks for the drawing example):
=B==D=
A=====E
=F==C=
- B towards the right of D
- F to the left of E
- F is between C and A
So it meets stmt 1 AND 2
However, the person opposite to D is F, so it's not adjacent to the person opposite to F (which is D). Sufficient to say NO.
So C is correct.
For this arrangement (thanks for the drawing example):
=B==D=
A=====E
=F==C=
- B towards the right of D
- F to the left of E
- F is between C and A
So it meets stmt 1 AND 2
However, the person opposite to D is F, so it's not adjacent to the person opposite to F (which is D). Sufficient to say NO.
So C is correct.
Last edited by pakaskwa on Fri Mar 06, 2009 4:35 am, edited 1 time in total.
-
- Newbie | Next Rank: 10 Posts
- Posts: 1
- Joined: Fri Feb 13, 2009 12:55 am
Is this a question where "no" would be sufficient to answer the question?
pakaskwa proved that D needs to be adjacent to F for the statement to hold true and then in statement I and II it seems like it satisfies the condition that D cannot be adjacent to F.
so i would guess D as my answer?
unless "towards the right" and "to the left" do not mean that they are directly adjacent? is there an official ans out there?
pakaskwa proved that D needs to be adjacent to F for the statement to hold true and then in statement I and II it seems like it satisfies the condition that D cannot be adjacent to F.
so i would guess D as my answer?
unless "towards the right" and "to the left" do not mean that they are directly adjacent? is there an official ans out there?
- gmat740
- MBA Student
- Posts: 1194
- Joined: Sat Aug 16, 2008 9:42 pm
- Location: Paris, France
- Thanked: 71 times
- Followed by:17 members
- GMAT Score:710
Q2.
The answer is E
Please check again.
I will post the answer once you have taken another shot of this
Q 2.
Stmt I
The number of students towards the left of Adam is 15 and Bryan is 10th from the right end
15 BRYAN ADAM 9 - >one possible combination (0 people between)
6 brian 8 adam -> 8 people
INSUFF
Stmt II
One third of the total number of students are in between Adam and Bryan
No idea on what the total number of students are
Together:
total = 18
8 BRIAN 6 ADAM 2
C
The answer is E
Please check again.
I will post the answer once you have taken another shot of this