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CR question
by gunjan arora - Thursday, 15 October 2009, 12:33 PM
 

In a certain wildlife park,park rangers are able to track movements of rhinosores because those animals wear radio collars.when, as often happens,a collar slips  off ,it is put back on.putting a collar on rhino involves immobilising the animal by shooting it with a tranquiliser dart. female rhinos that have been frequently recollared have significantly lower fertility rates than uncollered females .probably,therefore some substance in the tranqulizer inhibits fertility.

in evaluating the argument ,it would be most useful to determine which of the followng

1.Wether ther are more collered feamle rhinos tahn uncollered femaile rhinos,in the park.

2.how tranquliser that is use for immobilising rhinos differs,if at all, from tranqulisers used in working with other large mammals.

3.how often park rangers need to use tranqulizer darts to immobilise rhinos for reasons other than attatching radio collars.

4.wether male,rhinos in the wildlife park loses their collarsany more often than park's female rhino's do.

5.wehter radio collars are the only practical means that park rangers have for tracking the movements of rhinos in the park.

 

Re: CR question
by suman ranjan - Thursday, 15 October 2009, 07:01 PM
  I think answer should be 2. Important things to note down are as follows,
...Female rhinos...collaring with tranquilizer..effect on fertility..

so, in order to evaluate the argument we need to evaluate the effect of tranquilizer on other mammal's fertility..

1. has no info relating to fertility of female rhino
2. this will be useful in determining the effect of diff tranqs have on mammals
3. does not explaining fertility problem.
4. does not explaining fertility problem.
5. does not explaining fertility problem.


Re: CR question
by Takahiro Minagawa - Thursday, 15 October 2009, 08:28 PM
  It's a tough CR, but I've seen similar logic questions before.
You may be concerning that there is no right choice? right?

The conclusion is that
"The tranqulizer is the cause the lower fertility of female rhinos."

Tips: in the evaluation question,
you can test each choice by saying "Yes" or "No".
The right choice is to reverse the position depends on the Yes/No;
There are 2 possible patterns of right choice.

If Yes, it supports the argument, If No, it does not support  to the argument.
or
If No, it doses not support the argument, If Yes, it supports the argument.

Before applying the Yes/No test, you'd better eliminate the explicitly wrong answers

5: it is easiest one. "radio collars are the practical means" is not necesary info. because it is irrelevant
4: # of male is irrelevant

Then, we'll go on to evaluation test,

3: how often park rangers need to use tranqulizer darts to immobilise rhinos for reasons other than attatching radio collars.

even you can know the two opposite case, you cannot say which one support to the conclusion, because various cases can be assumed.

YES: many tranquilizer use
NO: no tranquilizer use

2:how tranquliser that is use for immobilising rhinos differs,if at all, from tranqulisers used in working with other large mammals.

YES: different kind of tranquliser are used in large mammals
NO: same kind of tranquiliser are used in large mammals

We cannot say which one support  the conclusion.

1:Whether there are more collered feamle rhinos than uncollered female rhinos,in the park.

This is the right answer.

YES:  collered female > uncollered female
NO:   uncollered female > collered female

For ease, I use examples
YES: 998 collered > 2 uncollered
No:  998 uncollered > 2 collered

Please focus on the sentence "female rhinos that have been frequently recollared have significantly lower fertility rates than uncollered females.

If case NO, there are only 2 collered rhinos among 1000 rinos.
And, and 1 or 2 rhino is frequently recollered.
And compared to the 998 uncollered females, recollered rhino's ferility is lower. Does it always mean the fertility is caused by the tranquliser?
It is more natural to regard the connection the collered rhinos and low fertility as a merely coincidence.
As you see, certain amount of collered rhinos are needed to support the conclusion.

In case YES,  the fact that collered rhinos is more than uncollered is supportive.

Taka



Re: CR question
by suman ranjan - Thursday, 15 October 2009, 11:28 PM
  I have a different thought..pls correct me if logic sounds vague..

The conclusion here is "therefore, some substance in the tranquilizer inhibits fertility."

its already an established fact that tranquilizers inhibit female rhino's fertility,but that is not the point here. Conclusion is about a substance present in that particular tranquilizer that is inhibiting the fertility, and how that can be evaluated..

So, in order to justify whether really something present in this specific tranquilizer is causing the lower fertility rates, it has to be compared with one that is used for other large mammals.
Hence, option (b) sounds good..

(a)I feel this option is irrelevant, as the numbers of collared vs. uncollared rhinos are irrelevant to fertility rates. Its already known that collared rhinos have lower fertility but that is not what the Q is about...its about tranquilizers..

Any more logic..welcomed..

Suman

Re: CR question
by gunjan arora - Friday, 16 October 2009, 01:14 PM
 

ok ..Guys....this is a Gmat prep question ..so i dont doubt its authenticity,,,if this had been from some other source i wud hv discarded the question "outrightly"....
 ,,this really is  a tuffy...answer is "C"...yes ..so it seems ,  none of us could get  the logic behind it ...even i thot the answer  to be "B".


so i wud request DT ot TG to pls help us out...

Re: CR question
by himanshu singh - Friday, 23 October 2009, 08:09 PM
  while you are evaluating the argument first of all you need to verify the source of argument or what are the implied assumptions in the argument. If you can prove the implied assumptions right or wrong you can either prove or disapprove the argument.Now read the line -"female rhinos that have been frequently recollared have significantly lower fertility rates than uncollered females .probably,therefore some substance in the tranqulizer inhibits fertility." now the implied assumption is tranquilisers are used only when you collar the female rhinos because the conclusion that frequently recollared rhinos have lower fertility because of some substance in tranquilisers assumes that it is only the frequently collared rhinos who receive doses of the tranqulisers . If you defeat the argument itself the entire conclusion would get nullified.So third option is the first thing you need to check on . 
Re: CR question
by Bishweshwar Pradhan - Sunday, 6 December 2009, 12:20 AM
 

It's a lil tough one, but take a note of few things in the argument. Then you can easily track the answer.

female rhinos that have been frequently recollared have significantly lower fertility rates than uncollered females

Only option (3) talks about the frequency of rhinos getting recollared.