GMAT考试：Testprep数学精解_GMAT数学

GMAT考试：Testprep数学精解

　　To symbolize this argument， let the clause he is innocent be denoted by I，and let the clause when we hold him under water for sixty seconds he will　not drown be denoted by ~D. Then the argument can be symbolized as

　　I~D

　　Therefore， I

　　Notice that this argument is fallacious： the conclusion he is innocent is　also a premise of the argument. Hence the argument is circularit proves what was already assumed. The argument affirms the conclusion then invalidly uses it to deduce the premise. The answer will likewise be fallacious.

　　We start with answer-choice 。 The sentence

　　To insure that the remaining wetlands survive， they must be protected by the governmentcontains an embedded if-then statement：

　　If the remaining wetlands are to survive， then they must be protected by the government.

　　This can be symbolized as SP. Next， the sentence This particular wetland　is being neglected can be symbolized as ~P. Finally， the sentence It will　soon perish can be symbolized as ~S. Using these symbols to translate the　argument gives the following diagram：

　　Therefore， ~S

　　The diagram clearly shows that this argument does not have the same structure as the given argument. In fact， it is a valid argument by contraposition.