1.     A milepost on the towpath read “21” on the side facing the hiker as she approached it and “23” on its back. She reasoned that the next milepost forward on the path would indicate that she was halfway between one end of the path and the other. However, the milepost one mile further on read “20” facing her and “24” behind.Which of the following, if true, would explain the discrepancy described above?
(A) The numbers on the next milepost had been reversed.
(B) The numbers on the mileposts indicate kilometers, not miles.
(C) The facing numbers indicate miles to the end of the path, not miles from the beginning.
(D) A milepost was missing between the two the hiker encountered.
(E) The mileposts had originally been put in place for the use of mountain bikers, not for hikers.

2.     Airline: Newly developed collision-avoidance systems, although not fully tested to discover potential malfunctions, must be installed immediately in passenger planes. Their mechanical warnings enable pilots to avoid crashes.Pilots: Pilots will not fly in planes with collision-avoidance systems that are not fully tested. Malfunctioning systems could mislead pilots, causing crashes.The pilots’ objection is most strengthened if which of the following is true?
(A) It is always possible for mechanical devices to malfunction.
(B) Jet engines, although not fully tested when first put into use, have achieved exemplary performance and safety records.
(C) Although collision-avoidance systems will enable pilots to avoid some crashes, the likely malfunctions of the not-fully-tested systems will cause even more crashes.
(D) Many airline collisions are caused in part by the exhaustion of overworked pilots.
(E) Collision-avoidance systems, at this stage of development, appear to have worked better in passenger planes than in cargo planes during experimental flights made over a six-month period.

3.     Guitar strings often go “dead”—become less responsive and bright in tone—after a few weeks of intense use. A researcher whose son is a classical guitarist hypothesized that dirt and oil, rather than changes in the material properties of the string, were responsible.Which of the following investigations is most likely to yield significant information that would help to evaluate the researcher’s hypothesis?
(A) Determining if a metal alloy is used to make the strings used by classical guitarists
(B) Determining whether classical guitarists make their strings go dead faster than do folk guitarists
(C) Determining whether identical lengths of string, of the same gauge, go dead at different rates when strung on various brands of guitars
(D) Determining whether a dead string and a new string produce different qualities of sound
(E) Determining whether smearing various substances on new guitar strings causes them to go dead

2007年GMAT考试最新逻辑推理试题训练十三_GMAT资料
2007年GMAT考试最新逻辑推理试题训练十五_GMAT资料