Clarinet reeds often lose their

Clarinet reeds often lose their freshness – become less responsive – after a few weeks of intense use.  One clarinetist has hypothesized that a buildup of oil, rather than changes in the material properties of the reed, were responsible.

Which of the following investigations is most likely to yield significant information that would help to evaluate the hypothesis?

A.  Determining what kind of wood is used to make the reeds used by jazz clarinetists.

B.  Determining whether jazz clarinetists make their reeds lose their freshness faster than do classical clarinetists.

C.  Determining whether identical lengths of reeds, of the same thickness, lose their freshness at different rates when put onto various brands of clarinets.  

D. Determining whether rubbing various substances on the new reed causes them to lose their freshness.

E. Determining whether a fresh reed and one that has lost its freshness produce different qualities of sound

 
The best answer is D.  The hypothesis has two parts: first, that intense use does not bring material changes that cause the reed to lose its freshness and, second, that oil causes the phenomenon.  The experiment suggested in choice D directly test this hypothesis by contaminating strings that are known to have their original material properties.  



Wheat has more nutritional value than rye. But since oats have more nutritional value than rice, it follows that wheat has more nutritional value than rice.

Any of the following, if introduced into the argument as an additional premise, makes the argument above logically correct EXCEPT:


A.  Wheat and oats have the same nutritional value.

B.  Rye has more nutritional value than oats.

C.  Rye has more nutritional value than rice.

D.  Rye and oats have the same nutritional value.

E. Oats have more nutritional value than wheat

The best answer is E.  The question asks for a different premise that does not make the argument logically correct.  Choice A leaves open the possibility that the conclusion of the argument is false.