Q7 - Superconductors are substances that

[giladedelman]

Thanks for posting! I misread your post at first and thought you were saying that A was wrong and E was right. I got pretty freaked out for a second!

Anyway, yes, (A) is correct because we're told that superconductors will only be economically feasible if there's a substance that conducts at over -148 degrees C, but the only substances that are contenders max out at -160 degrees. If the only possible substances don't work, then there is nothing that will work.

(E), on the other hand, is incorrect because we only know these won't become economically feasible as superconductors -- but maybe there will be other uses for these alloys that will be economically feasible! Maybe they're really efficient for car manufacturing, or something!

(B) is the opposite of what we're told -- these are the only possible substances.

(C) is also the opposite -- it has to be above, not below, -148.

(D) is incorrect because we're told -160 is the maximum for these alloys, which certainly doesn't prohibit them from conducting at lower temperatures -- in fact, it strongly implies that they do.

Does that answer your question?


#officialexplanation

[alinanny]

I chose A but I have a hard time understanding why E is incorrect.
Any help is appreciated.

[alinanny]

Thanks for posting! I misread your post at first and thought you were saying that A was wrong and E was right. I got pretty freaked out for a second!

Anyway, yes, (A) is correct because we're told that superconductors will only be economically feasible if there's a substance that conducts at over -148 degrees C, but the only substances that are contenders max out at -160 degrees. If the only possible substances don't work, then there is nothing that will work.

(E), on the other hand, is incorrect because we only know these won't become economically feasible [b]as superconductors -- but maybe there will be other uses for these alloys that will be economically feasible! Maybe they're really efficient for car manufacturing, or something! [/b]
(B) is the opposite of what we're told -- these are the only possible substances.

(C) is also the opposite -- it has to be above, not below, -148.

(D) is incorrect because we're told -160 is the maximum for these alloys, which certainly doesn't prohibit them from conducting at lower temperatures -- in fact, it strongly implies that they do.

Does that answer your question?

Thank you. This makes so much sense now!

[kmewmewblue]

What is "above minus 148"?

-150 above?

-148

-145 below?

What is "no higher than 160"?

What is this based on? "minus" only?
It is very confusing.
Thanks

[ManhattanPrepLSAT1]

What is "above minus 148"?

Above minus 148 degrees is anything warmer than minus 147 degrees. So minus 120 degrees would be above minus 148 degrees. Also 70 degrees (a typical California day) would be above minus 148 degrees.

What is "no higher than 160"?

No higher than minus 160 degrees means minus 161 degrees or colder. So minus 200 degree (really cold!) would be no higher than minus 160 degrees.

I know the math can be tricky and can get one easily turned around here. Hope that helps!

[al2568]

How would you diagram this question?

[ManhattanPrepLSAT1]

While this full of conditionals, I probably wouldn't notate this one, unless I was really struggling to connect the dots.

1. If superconductors are economically feasible, then there is a substance that superconducts at a temperature above minus 148 degrees celsius.

EF --> SA(148)

2. If there is a substance that superconducts at a temperature above minus 148 degrees celsius, then it must be an alloy of niobium and germanium.

3. SA(148) --> A(N+G)

No substance that superconducts at a temperature above minus 148 degrees celsius.

~SA(148)

** I know the third statement isn't word for word, but it does get at the meaning of the third statement.

Combining the first and third statement we can infer answer choice (A).

[kyuya]

Wanted to give my thoughts here.

If the use of superconductors are economic feasible ---> there is a substance that super conducts at a temperature above minus 148 degrees (or in other words, 147 and above) ---> that substance must be an alloy or niobium and germanium.

BUT, unfortunately, "such alloys" (in this case, alloy of niobium and germanium) superconduct at temperatures no higher than minus 160 degrees Celsius.

Wait.. what did we need to know about economically feasible options again? Right.. they would be able to conduct at temperatures above minus 148. ABOVE, meaning 147 and below.

But if these can conduct at no higher than minus 160, that means they DEFINITELY cannot go to 147, because the highest they can go is 160, but they are free to go LOWER, 161--- and onward downward.

So what can we infer? Well.. it looks like superconductors cannot be economically feasible. Hey, thats what (A) says.

Lets check out the wrong answers.

(B) The latter half of this conditional statement is just unsupported. We don't know anything about other substances.

(C) We don't know this. This suggests that being able to super conduct at temperatures below minus 148 is SUFFICIENT, but we don't know this. It seems to suggest in the stimulus that rather than a sufficient condition, it was a necessarily condition. Therefore we cannot draw conclusions from it.

(D) Actually the passage suggests otherwise. It says "such alloys superconduct at temperatures no higher than minus 160 degrees celsius" in the stimulus.

(E) We don't know if it will NEVER be economically feasible. Maybe in the future some new technology will make it possible, but cannot draw inferences into the past based on the information we are given.

I think this question was difficult for Four reasons primarily:

1.) I think the difficulty of it is partially with the temperatures - if you're like me it was a bit irritating keeping track of above and below when we were speaking of a negative temperature. Sometimes I'd have to remind myself the temperatures were negative so above and below were a bit more counter intuitive.

2.) Furthermore, if you don't catch the referential phrasing "unfortunately SUCH ALLOYS..." you'll probably be lost. You must realize its referring to the niobium and germanium.

3.) You've gotta realize germanium and niobium are not important to understand. You could easily replace them with "X and Y" and your head of that helps. It is a superficial difficulty. The structure and logic of the argument is not contingent on recognizing scientific terms, something we get reminded of in tough science reading comp passages.

4.) Finally, I think this question is made difficult by conditional statements if you are not clear with your indicator words. You must know that UNLESS means you negative the sufficient condition or it may be hard for you to make the conditional chain necessary that leads you quickly to the right answer.

[ganbayou]

I'm confused...

I feel like the stimulus contradicts itself. It says "If there is such a substance, that substance must be an alloy of niobium and germanium."
Why did the author mention this-there are those substances and they are the only ones that can meet the requirement-if they do not meet the requirement?
3rd sentence and 4th sentence (combined with the 2nd sentence) seem contradict each other to me...

Thank you

[tommywallach]

Hey Ganbayou,

They don't, because it's a hypothetical. It's saying if there is, it would have to be a certain way. That doesn't mean there IS something that fits the description, only that if there is, it would have to be as described.

-t