請問LSAT14（II）Q24、25

schlafen

    

24.   A
certain airport security scanner designed to detect explosives in luggage will
alert the scanner’s operator whenever the piece of luggage passing under the
scanner contains an explosive. The scanner will erroneously alert the operator
for only one percent of the pieces of luggage that contain no explosives. Thus
in ninety-nine out of a hundred alerts explosives will actually be present.

    

The reasoning in the argument is flawed
because the argument

    

(A) ignores the
possibility of the scanner’s failing to signal an alert when the luggage does
contain an explosive

    

(B) draws a
general conclusion about reliability on the basis of a sample that is likely to
be biased

    

(C) ignores the
possibility of human error on the part of the scanner’s operator once the
scanner has alerted him or her

    

(D) fails to
acknowledge the possibility that the scanner will not be equally sensitive to
all kinds of explosives（E）

    

(E) substitutes
one group for a different group in the statement of a percentage

大全答案給E，但為什麼不是A？


    



    

25.   Unless
negotiations begin soon, the cease-fire will be violated by one of the two
sides to the dispute. Negotiations will be held only if other countries have
pressured the two sides to negotiate; an agreement will emerge only if other
countries continue such pressure throughout the negotiations. But no
negotiations will be held until international troops enforcing the cease-fire
have demonstrated their ability to counter any aggression from either side,
thus suppressing a major incentive for the two sides to resume fighting.

    

If the statements above are true, and if
negotiations between the two sides do begin soon, at the time those
negotiations begin each of the following must also be true EXCEPT:

    

(A) The
cease-fire has not been violated by either of the two sides.

    

(B)
International troops enforcing the cease-fire have demonstrated that they can
counter aggression from either of the two sides.

    

(C) A major
incentive for the two sides to resume hostilities has been suppressed.

    

(D) Other
countries have exerted pressure on the two sides to the dispute.（A）

    

(E) The
negotiations’ reaching an agreement depends in part on the actions of other
countries.

這一題則是完全不理解，答案是A。BCDE都符合前提，OK，但A不是也符合嗎？如果兩邊已經打起來還要negotiate嗎？A不是也符合前提嗎？請高人解惑，謝謝。