PT7.S1.Q16 - Eight years ago hunting was

wkim2015

Can anyone please tell me how the answer choice (B) is correct and (C) is wrong?? I just can't get myself to understand. This just sounds like the question is playing word games.

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Kateryna

First of all did you identify the question type? Answer C can be right and answer B can be wrong and vice versa depending on question type.

So lets see. This is MSS question. For this question type you need to identify which answer choice is most provable based on the stimulus. The right answer is the one that is most supported by the text. When choosing between two answers, look for the one that is safest - that is the one that requires the least number of leaps from the information in the stimulus.

Coming back to the question and answers B and C...

Answer C. Do we know anything about total amount of light reflected? No. We know that it reflects 60 times less per unit. To make the inference about total amount of light you will need to bridge those two. It will require you to make an extra leap (extra assumption) about the fact that if it is less per unit it is less for total amount. While it sounds like common sense, remember, we do not use common sense to pick the answer choice.

Answer B. Requires zero leaps. The passage clearly states that it is 60% less than what it was though to be. Answer restates that in different words "previous estimates were too low." Same thing phrased differently.

To identify the right answer you need to have a clear sense of the question type and what that question type requires you to do.

Hope that helps.

FixedDice

There's a rule against posting direct quotes from PTs.

paulmv.benthem

While I think it's important to be clear on the question type, as @Kateryna is suggesting, I would encourage you to think carefully about what is being described in the stimulus and what the implications are. While the correct answer choice does not require you to assume anything, it is requiring you to make an inference that is NOT directly stated in the stimulus.

What's important to recognize is the scientists are estimating the mass of comets based on the amount of light that is reflected, with a positive correlation existing between the two. So, let's say that prior to the probe there was 10,000 units of light being reflected from Halley's comet that was detectable by scientists, leading them to believe that it had a mass of 1,000 kilograms. This estimation would be based on a specific understanding of how much light is reflected per unit of mass by Halley's comet. The probe, however, reveals that this understanding is incorrect, and the amount of light that is reflected is actually 60% less per unit of mass than previously thought. So, the amount of light that is being reflected is still the same (making AC-C incorrect), but the estimation of the mass needs to be reappraised in light of this evidence. And, since each unit of mass would be reflecting less light than previously thought, that would mean that Halley's comet would have to be larger than previously thought in order to reflect the amount of light that it does (which is what is suggested in AC-C) .

Does that make sense...it's getting late where I am, so I might just be spitting marbles all over your thread.

FixedDice

(C) is wrong because the new data doesn't imply anything about the total amount of light reflected by the comet. The comet's components reflect much less light than previously believed. That is compatible with the comet reflecting the same amount of light; the comet just could be a lot bigger, for instance.

(B) is right because the comet's components reflect much less light. The comet reflects a certain amount of light, but its components are a lot less reflective than previously calculated. This means that to reflect the same amount of light, much, much more of the reflective materials would be needed. If the comet holds more materials, it would be a lot heavier.

wkim2015

thanks so much everyone! I really appreciate the help! That makes so much more sense now i also didn't know about this rule... am i missing something?

paulmv.benthem

@wkim2015 said:
thanks so much everyone! I really appreciate the help! That makes so much more sense now i also didn't know about this rule... am i missing something?

No worries(ish)! Copywrite issues mainly. Here's a quick page you could check out...

https://7sage.com/discussion/#/categories/forum-rules

kennmh20

@FixedDice said:
(C) is wrong because the new data doesn't imply anything about the total amount of light reflected by the comet. The comet's components reflect much less light than previously believed. That is compatible with the comet reflecting the same amount of light; the comet just could be a lot bigger, for instance.

(B) is right because the comet's components reflect much less light. The comet reflects a certain amount of light, but its components are a lot less reflective than previously calculated. This means that to reflect the same amount of light, much, much more of the reflective materials would be needed. If the comet holds more materials, it would be a lot heavier.

I am writing this out to further my understanding of why C is wrong. The explanation above is perfectly acceptable and was very helpful.

Following up on it, all we know from the text is that the material of Halley's comet reflected considerably less light per unit than was previously thought. Hypothetically, the scientists could have, and probably did, measured the amount of light reflecting correctly, but could have been surprised at the low amount of light that was being reflected. Learning more about the material simply gives scientists an explanation about why the light they very well could have previously measured correctly was much lower than they would have thought (based off their previous knowledge of comets, materials, etc.).

B, on the other hand, takes an extra step, and equates light to mass. Because the light being reflected is measured at much less than the supposed standard, it is completely supported that scientists could have misjudged the true size of the comet, despite accurate light measurements. It is not the light measurements that previous estimates got wrong. Instead, the new evidence about the material changed the conversion rate of light--> mass. B deals with this conversion of light to mass, and thus is supported by the text.