Superconductors are substances that conduct electricity without resist

Question

Superconductors are substances that conduct electricity without resistance at low temperatures. Their use, however, will never be economically feasible, unless there is a substance that superconducts at a temperature above minus 148 degrees Celsius. If there is such a substance, that substance must be an alloy of niobium and germanium.Unfortunately, such alloys superconduct at temperatures no higher than minus 160 degrees Celsius.

If the statements above are true, which one of the following must also be true?

(A) The use of superconductors will never be economically feasible.
(B) If the alloys of niobium and germanium do not superconduct at temperatures above minus 148 degrees Celsius, then there are other substances that will do so.
(C) The use of superconductors could be economically feasible if there is a substance that superconducts at temperatures below minus 148 degrees Celsius.
(D) Alloys of niobium and germanium do not superconduct at temperatures below minus 160 degrees Celsius.
(E) No use of alloys of niobium and germanium will ever be economically feasible.

RastogiSarthak99 · Answer

both options C and D were confusing because of the word "below" and that's where they are wrong. Hence, A.

Uswetha · Answer

when the question stem says must be true, does it mean assumption or inference?? I expected it to be an assumption question and opted for B. If it was inference, answer would be A

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vanam52923 · Answer

if it is given : 
If the statements above are true, which one of the following must also be true?

then it is inference bcz we are considering the given passage as true nd on basis of that we have to find which of floowing statemnt is true.

if it is given :

if the above argument to be true,which of the following must be true then it is an assumption.
means if any of given option is true then the only argument will hold so it is assumption bcz assumption must be true for assumption to hold.

prateekchugh · Answer

KAPLAN OFFICIAL EXPLANATION

(A) Inference (Formal Logic)

When you spot Formal Logic keywords in an Inference question, know that the correct answer will often result from forming the contrapositive. Don’t let the arcane scientific jargon distract you from the task at hand. The stimulus tells us that superconductors will never be economically feasible unless there is a substance that super conducts above -148 degrees Celsius. Sounds like a sufficient necessary relationship, right? We can translate this sentence, which is in “No X unless Y” form, into the equivalent “If X then Y” thusly: “If econ. feas. → supercond. above -148” Contraposing this statement will give us “If cannot supercond. above -148 → NOT econ. feas.” Then we learn that the only substances that could possibly fulfill the necessary condition (superconducting above minus 148 Celsius) are alloys of niobium and germanium, which the last sentence tells us cannot superconduct at temperatures any higher than minus 160. If niobium and germanium alloys can’t superconduct above minus 160, they certainly can’t superconduct above minus 148, which triggers our contrapositive. We can conclude then that superconductors can’t be economically feasible, which is exactly what  (A)  says.

(B)  cannot be true if the stimulus is true. The third sentence of the stimulus tells us that the only substances that can superconduct at temps above minus 148 degrees would be alloys of niobium and germanium. So if those substances can’t do it, no others can.

(C)  gets the logic of the stimulus backwards. To be useful, the substance needs to superconduct above minus 148, not below. After all, the niobium/germanium alloys already superconduct below minus 148.

(D)  directly contradicts the stimulus. We know from the stimulus that alloys of niobium and germanium do not superconduct at temps higher than minus 160, which means that they must superconduct at temps below minus 160.

(E)  is tempting, but ultimately outside the scope because we can only make inferences about the economic feasibility of the use of superconductors. It’s entirely possible that alloys of niobium and germanium could be economically feasible in other functions.

ravigupta2912 · Answer

Super confused with what "higher" "lower" means in the context of temperatures.

sssanskaar · Answer

It's ultimately between A and E.

E : NO USE OF alloys of niobium and germanium will ever be economically feasible.

- we are not talking about any uses other than that of superconductors. Hence, to say that NO USE of alloys (superconductors or anything else as well) will be economically not feasible is a good enough factor to eliminate this option.

VerbalBot · Answer

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Superconductors are substances that conduct electricity without resist

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