Critical Reasoning

1. Sharks have a higher ratio of cartilage mass to body mass than any other organism. They also have a greater resistance to cancer than any other organism. Shark cartilage contains a substance that inhibits tumor growth by stopping the development of a new blood network. In the past 20 years, none of the responses among terminal cancer patients to various therapeutic measures has been more positive than the response among those who consumed shark cartilage.
If the claims made above are true, then each of the following could be true EXCEPT:
(A) No organism resists cancer better than sharks do, but some resist cancer as well as sharks.
(B) The organism most susceptible to cancer has a higher percentage of cartilage than some organisms that are less susceptible to cancer.
(C) The substance in shark cartilage that inhibits tumor growth is found in most organisms.
(D) In the past 20 years many terminal cancer patients have improved dramatically following many sorts of therapy
(E) Some organisms have immune systems more efficient than a shark's immune system.

maihuna wrote:1. Sharks have a higher ratio of cartilage mass to body mass than any other organism. They also have a greater resistance to cancer than any other organism. Shark cartilage contains a substance that inhibits tumor growth by stopping the development of a new blood network. In the past 20 years, none of the responses among terminal cancer patients to various therapeutic measures has been more positive than the response among those who consumed shark cartilage.
If the claims made above are true, then each of the following could be true EXCEPT:
(A) No organism resists cancer better than sharks do, but some resist cancer as well as sharks.
(B) The organism most susceptible to cancer has a higher percentage of cartilage than some organisms that are less susceptible to cancer.
(C) The substance in shark cartilage that inhibits tumor growth is found in most organisms.
(D) In the past 20 years many terminal cancer patients have improved dramatically following many sorts of therapy
(E) Some organisms have immune systems more efficient than a shark's immune system.

I think A because the passage explicitly states that "Sharks have a greater resistance to cancer than any other organism". So, that means no organism resists cancer as well as Sharks... What is the OA?

I would go with E because the argument does not talks about immune system at all. So we can't say whether E is true or false as we don't have any information about it.

maihuna wrote:1. Sharks have a higher ratio of cartilage mass to body mass than any other organism. They also have a greater resistance to cancer than any other organism. Shark cartilage contains a substance that inhibits tumor growth by stopping the development of a new blood network. In the past 20 years, none of the responses among terminal cancer patients to various therapeutic measures has been more positive than the response among those who consumed shark cartilage.
If the claims made above are true, then each of the following could be true EXCEPT:
(A) No organism resists cancer better than sharks do, but some resist cancer as well as sharks.
(B) The organism most susceptible to cancer has a higher percentage of cartilage than some organisms that are less susceptible to cancer.
(C) The substance in shark cartilage that inhibits tumor growth is found in most organisms.
(D) In the past 20 years many terminal cancer patients have improved dramatically following many sorts of therapy
(E) Some organisms have immune systems more efficient than a shark's immune system.

I would go with E because the argument does not talks about immune system at all.

The fact that the passage does not discuss immune system is exactly why choice E could be true. In inference, everything in the passage must be true and everything outside of the passage could be true or could be false. This is a could be true except question. So, the four wrong answers are all things that could be true while the correct answer is something the passage has proven must be false. As mridula points out, the second sentence of the passage proves that choice A must be false.

_______

For example, if I say "all televisions are black", then could it be true that "all martians are green"? Of course it can. So, if it is outside the scope, it could very easily be true (or false). The correct answer to a must be question is something that is within the scope of the passage. And this question is actually a must be question (four wrongs are could be trues while the correct answer is something that must be false).

It's D!

boazkhan wrote:It's D!

Are you saying that the official answer is choice D? Or is that just your opinion?

If it's just your opinion, then you should make that clear by saying "I think it's D" or "IMO D". On the other hand, if the official answer is in fact choice D, then you should also make that clear by saying "the accredited response is choice D" or "OA: D". (We don't want members to get bad information.)

If the OA to this question is choice D, then the OA is incorrect.

But, I am sure what you meant is that it was just your opinion that D was correct. You likely think choice D is the correct answer (ie, the one that cannot be true) because of the last sentence of the passage:

In the past 20 years, none of the responses among terminal cancer patients to various therapeutic measures has been more positive than the response among those who consumed shark cartilage.

So, this means that, of all the cancer therapies in the last 20 years, shark cartilage has been the single best; this DOES NOT establish that every other therapy was garbage. It may well be true that there are other therapies that have also resulted in "dramatic improvement"; however, shark cartilage has yielded the most dramatic improvement.

This is a typical relative vs absolute error type you've fallen into here. Now, you know a certain kind of wrong answer to avoid on test day.

The correct answer must be choice A, as per my comments in my first post in this thread.

What's the OA please?

Testluv, what about C? The passage states that "Shark cartilage contains a substance that inhibits tumor growth ". The way I interpret this statement is that the so-called substance is unique to Sharks which helps them resist cancer. Also, this particular statement in the passage comes immediately after the author says "They also have a greater resistance to cancer than any other organism.", which I think has been done to establish a cause-effect relationship (i.e. because of the presence of this very substance in their cartilage, sharks are able to resist cancer.) Hence option C which states that substance is found in most organisms cannot be true.

Waiting for the OA please.

First of all, choice A is definitely correct because it directly contradicts the second sentence of the passage.

The second sentence of the passage tells us:

They also have a greater resistance to cancer than any other organism.

In other words, it is IMPOSSIBLE that any other organism is equal to the shark when it comes to resisting cancer. Hence, choice A, which reads:

(A) No organism resists cancer better than sharks do, but some resist cancer as well as sharks.

must be false. The portion of choice A that I've emboldened is in direct contradiction with the second sentence of the passage.

Turning to choice C, it reads:

(C) The substance in shark cartilage that inhibits tumor growth is found in most organisms.

You may well find choice C unlikely. However, it still could be true because no part of the passage contradicts choice C. The passage never ever establishes that the substance that inhibits tumor growth is unique to shark cartilage. (Instead, it could be the case that the substance is present in most organisms but present in unusually high quantities in shark cartilage).

_________

Here are some important takeways. Let's start by thinking about a normal inference question, where the right answer MUST BE TRUE. In a MUST BE TRUE question, the right answer is something that must be true while the four wrong answers could be false. The difficulty there is distinguishing a choice that is most probably true from one that is necessarily true. But it doesn't matter if it is very probably true; if it could be false, then it is wrong.

Similarly, here, the correct answer is something that MUST BE FALSE. The four wrong answers are things that could be true. The difficulty here is disinguishing between a choice that you might find very likely to be false (like choice C) from one that the text of the passage has proven necessarily false.

Now, I say "difficulty" but it isn't all that difficult if you internalize a good approach. Step 1 of the Kaplan method is to read the question stem. Upon realizing that this was an inference family question, the well-trained Kaplan student would have characterized the choices and said this in her head: "This is an EXCEPT question. The four wrong answers COULD BE TRUE but I don't care about those. I have to find the answer that one or more sentences in the passage has proven MUST BE FALSE."

And, if she's really confident, after seeing that choice A did indeed contradict a sentence in the passage, the well-trained Kaplan student would have selected choice A, and then exited the question without even reading the remaining answer choices. (As there is always one and only one correct answer).

I think ans should be A
Two ques here

• Whats the OA ?
  Whats the SOURCE of the question

Thanks TestLuv, OA is A.

maihuna wrote:Thanks TestLuv, OA is A.

No problem.

lav brings up a question I myself meant to ask: What is the source of this question?

I don't think there's any could be true except questions in the CR section of the OG. However, I'm pretty sure I've seen one or two from GMATPREP.

Testluv wrote:

maihuna wrote:Thanks TestLuv, OA is A.

No problem.

lav brings up a question I myself meant to ask: What is the source of this question?

I don't think there's any could be true except questions in the CR section of the OG. However, I'm pretty sure I've seen one or two from GMATPREP.

Hi TestLuv, It is from LSAT. Though I do not do lot of LSAT questions but was surprised to see such pattern myself, can you please share the gmatprep Q that you have seen(in case you have them).

Testluv wrote:First of all, choice A is definitely correct because it directly contradicts the second sentence of the passage.

The second sentence of the passage tells us:

They also have a greater resistance to cancer than any other organism.

In other words, it is IMPOSSIBLE that any other organism is equal to the shark when it comes to resisting cancer. Hence, choice A, which reads:

(A) No organism resists cancer better than sharks do, but some resist cancer as well as sharks.

must be false. The portion of choice A that I've emboldened is in direct contradiction with the second sentence of the passage.

Turning to choice C, it reads:

(C) The substance in shark cartilage that inhibits tumor growth is found in most organisms.

You may well find choice C unlikely. However, it still could be true because no part of the passage contradicts choice C. The passage never ever establishes that the substance that inhibits tumor growth is unique to shark cartilage. (Instead, it could be the case that the substance is present in most organisms but present in unusually high quantities in shark cartilage).

_________

Here are some important takeways. Let's start by thinking about a normal inference question, where the right answer MUST BE TRUE. In a MUST BE TRUE question, the right answer is something that must be true while the four wrong answers could be false. The difficulty there is distinguishing a choice that is most probably true from one that is necessarily true. But it doesn't matter if it is very probably true; if it could be false, then it is wrong.

Similarly, here, the correct answer is something that MUST BE FALSE. The four wrong answers are things that could be true. The difficulty here is disinguishing between a choice that you might find very likely to be false (like choice C) from one that the text of the passage has proven necessarily false.

Now, I say "difficulty" but it isn't all that difficult if you internalize a good approach. Step 1 of the Kaplan method is to read the question stem. Upon realizing that this was an inference family question, the well-trained Kaplan student would have characterized the choices and said this in her head: "This is an EXCEPT question. The four wrong answers COULD BE TRUE but I don't care about those. I have to find the answer that one or more sentences in the passage has proven MUST BE FALSE."

And, if she's really confident, after seeing that choice A did indeed contradict a sentence in the passage, the well-trained Kaplan student would have selected choice A, and then exited the question without even reading the remaining answer choices. (As there is always one and only one correct answer).

Hi TestLuv,
When I did this question, I knew that something is wrong with "A".
No organism resists cancer better than sharks do, "but some resist cancer as well as sharks"
But I chose B because I thought none of the other options fit in.

Here is how I interpreted the statement.
"No organisim resists cancer better than sharks do" ----> This is the second sentence.
"but some resist cancer as well as sharks" --> This can also be true....
It only says some can resist cancer and can resist shark.
for e.g a blue whale. Suppose, a blue whale can also resist cancer, but not better than a shark can
and assuming that a shark wont' attack a whale, then the statement could be true right ?

So when you say, "In other words, it is IMPOSSIBLE that any other organism is equal to the shark when it comes to resisting cancer" I don't understand how it implies "equal"
please help.

Thanks
TOPGMAT

maihuna wrote:1. Sharks have a higher ratio of cartilage mass to body mass than any other organism. They also have a greater resistance to cancer than any other organism. Shark cartilage contains a substance that inhibits tumor growth by stopping the development of a new blood network. In the past 20 years, none of the responses among terminal cancer patients to various therapeutic measures has been more positive than the response among those who consumed shark cartilage.
If the claims made above are true, then each of the following could be true EXCEPT:
(A) No organism resists cancer better than sharks do, but some resist cancer as well as sharks.
(B) The organism most susceptible to cancer has a higher percentage of cartilage than some organisms that are less susceptible to cancer.
(C) The substance in shark cartilage that inhibits tumor growth is found in most organisms.
(D) In the past 20 years many terminal cancer patients have improved dramatically following many sorts of therapy
(E) Some organisms have immune systems more efficient than a shark's immune system.

A friendly heads-up. This is an official LSAT question - LSAC doesn't take kindly to its questions being put up on the web, and has a company patrolling the web to protect its copyrights. I suggest you take it down.