GRE网络课堂学习笔记-逻辑[5]

6. Questions 13-18

A breeder has ten birds:

　　Kind 　　　　　Male 　　　　　Female
Goldfinches 　　　　H 　　　　　　J, K
Lovebirds 　　　　　M 　　　　　　　N
Parakeets 　　　Q, R, S 　　　　　T, W

The breeder exhibits pairs of birds consisting of one male and one female of the same kind. At most two pairs can be exhibited at a time; the remaining birds must be distributed between two cages. The breeder is constrained¹ by the following conditions:
Neither cage can contain more than four birds.
Any two birds that are both of the same sex and of the same kind as each other cannot be caged together.
Whenever either J or W is exhibited, S cannot be exhibited.

(13). Which one of the following is a possible assignment of the birds?

　　First Cage 　　　　　Second Cage 　　　　　　　　Exhibition
(A) H, M, N 　　　　　　　J, K, S 　　　　　　　　　　　Q, R, T, W
(B) K, M, Q 　　　　　　　N, R, W 　　　　　　　　　　H, J, S, T
(C) K, Q, S 　　　　　　　R, T, W 　　　　　　　　　　　H, J, M, N
(D) H, J, M, R 　　　　　　K, N, S, W 　　　　　　　　　Q, T
(E) H, J, M, R, W 　　　　K, N, S 　　　　　　　　　　　Q, T, W

(14). Which one of the following lists two pairs of birds that the breeder can exhibit at the same time?
(A) H and J; M and N
(B) H and J; S and T
(C) H and K; M and N
(D) H and K; R and W
(E) M and N; S and W

(15). If Q and R are among the birds that are assigned to the cages, then it must be true that
(A) H is exhibited
(B) K is exhibited
(C) N is exhibited
(D) J is assigned to one of the cages

(E) T is assigned to one of the cages

(16). If Q and T are among the birds assigned to the cages, which one of the following is a pair of birds that must be exhibited?
(A) H and J
(B) H and K
(C) M and N
(D) R and W
(E) S and W

(17). Which one of the following CANNOT be true?
(A) One pair of parakeets are the only birds exhibited together.
(B) One pair of goldfinches and one pair of lovebirds are exhibited together.
(C) One pair of goldfinches and one pair of parakeets are exhibited together.
(D) One pair of lovebirds and one pair of parakeets are exhibited together.
(E) Two pairs of parakeets are exhibited together.

(18). If S is one of the birds exhibited, it must be true that
(A) H is exhibited
(B) M is exhibited
(C) K is assigned to a cage
(D) N is assigned to a cage
(E) R is assigned to a cage

KEYS: DDDDBE