LSAT 逻辑游戏题（5）

sdcar2010 · 发表于 2010-11-18 09:40:11

Seven dogs: A, B, C, D, E, F, and G, will shit on the laps of two British men, James and Hudson. Dogs A, B, C, and D are male, and dogs E, F, and G are female. Each dog will shit on exactly one of the two men, and each man will be shit on by at least one dog.

The following conditions must apply:

At least two male dogs will shit on James.
At least two female dogs will shit on Hudson.
If D shits on James, then F does not shit on Hudson.
If D does not shit on James, then G shits on James.
A and B will shit on the same man.

1. Which one of the following could be a complete and accurate list of the dogs that shit on James?

(A) A, B, D, F
(B) A, B, E
(C) A, B, E, D
(D) A, C, D, F
(E) C, G

2. If G shits on James, which one of the following dogs must also shit on James?

(A) B
(B) C
(C) D
(D) E
(E) F

3. If B shits on Hudson, then which one of the following must be true?

(A) A shits on the same person as C
(B) A shits on the same person as F
(C) B shits on the same person as C
(D) C shits on the same person as F
(E) D shits on the same person as G

4. If G does not shit on James, which one of the following dogs CANNOT shit on Hudson?

(A) A
(B) B
(C) C
(D) D
(E) E

5. If exactly 4 dogs shit on James, which one of the following is a pair of dogs, both of which must be among those that shit on him?

(A) A, B
(B) B, D
(C) B, G
(D) C, G
(E) D, F

6. Each of the following could be true EXCEPT:

(A) All 4 male dogs shit on James.
(B) All 3 female dogs shit on Hudson.
(C) Exactly 5 dogs shit on James.
(D) Exactly 4 dogs shit on Hudson.
(E) Exactly 3 dogs shit on James.

7. Which one of the following dogs must shit on Hudson?

(A) A
(B) B
(C) C
(D) D
(E) E

taoransk · 发表于 2010-12-5 12:07:58

7Dog: ABCD=[M], EFG=[F]
2People: JH

-- 2+[M] on J (J = at least 2 of ABCD)
-- 2+[F] on H (H = at least 2 of EFG)
-- D(J)-->F(J) ==> F(H)-->D(H)-->G(J)-->E&F(H)
-- D(H)-->G(J) ==> G(H)-->D(J)-->F(J)-->E&G(H)
-- A<-->B

If F(H):
J = ABG+(C) (If J=/=A/B, J can't have 2[M], once has A/B, it will be A&B)
H = DEF+(C) (G=J, H must has 2 of EFG, thus EF left)

If G(H):
J = D+(A&B/C)+F+?
H = GE+?

1. Which one of the following could be a complete and accurate list of the dogs that shit on James?

(B) F(H)-->D(H)-->G(J)
(C) Rule 3, F(H)-->D(H)
(D) Rule 5
(E) Rule 1

Answer: (A)

2. If G shits on James, which one of the following dogs must also shit on James?

G(J)-->E&F(H) [(D)(E) incorrect]
F(H)-->D(H) [(C) incorrect]
If F(H):
J = ABG+(C) (If J=/=A/B, J can't have 2[M], once has A/B, it will be A&B)
H = DEF+(C) (G=J, H must has 2 of EFG, thus EF left)

Answer: (A)

3. If B shits on Hudson, then which one of the following must be true?

B(H)-->A(H)-->C&D(J)
D(J)-->F(J)-->EG(H)
Thus if B(H):
J = CDF
H = ABEG

Answer: (D)

4. If G does not shit on James, which one of the following dogs CANNOT shit on Hudson?

G(H)-->D(J)-->F(J)-->E&G(H)

Answer: (D)

5. If exactly 4 dogs shit on James, which one of the following is a pair of dogs, both of which must be among those that shit on him?

J=4, H=3
H must has 2 of EFG, A/B-->A&B, Thus A&B(J)

Answer: (A)

6. Each of the following could be true EXCEPT:

J=(AB)/(CD),H=(CD)/(AB)+EFG, but F(H)-->G(J);

Answer: (C)

7. Which one of the following dogs must shit on Hudson?

(这个凭直觉-.-前面推的多了,懒得算了)

Answer: (E)

sdcar2010 · 发表于 2010-12-5 12:36:45

1. A
2. A
3. D
4. D
5. A
6. B
7. E

LS is impressive. Only 6 needs further work.

taoransk · 发表于 2010-12-5 16:23:24

J=CG,H=ABDEF

My bad, forgot the possibility on 1M+1F

6. Each of the following could be true EXCEPT:

(A) J=ABCDF,H=EG
(B) All 3 female dogs shit on Hudson.
(C) J=CG,H=ABDEF
(D) J=ABG,H=CDEF
(E) J=ABG,H=CDEF

Only (B) Left

But can anyone prove (B) is valid by itself?

so hard for me though

sdcar2010 · 发表于 2010-12-6 06:47:26

Seven dogs: A, B, C, D, E, F, and G, will shit on the laps of two British men, James and Hudson. Dogs A, B, C, and D are male, and dogs E, F, and G are female. Each dog will shit on exactly one of the two men, and each man will be shit on by at least one dog.

The following conditions must apply:

At least two male dogs will shit on James.
At least two female dogs will shit on Hudson.
If D shits on James, then F does not shit on Hudson.
If D does not shit on James, then G shits on James.
A and B will shit on the same man.

Could 6(B) "All 3 female dogs shit on Hudson" be true?

Let's take a look on D, who has to shit on either James or Hudson. If D shits on James, one female dog F does not shit on Hudson. If D does not shit on James, then one female dog G does not shit on Hudson. Therefore, there is no way for all three female dogs to shit on Hudson.

LSAT 逻辑游戏题（5）

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