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M07-18

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11 Jul 2017, 22:24
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IanStewart wrote:
Is this one of your questions, Bunuel? It's a really good question - it's logically tricky, but the setup is elegantly simple, like in many real high-level GMAT problems.

In case it helps anyone, when I read Statement 1, I rephrased it this way: "if you pick two snakes from the box, you will never pick two cobras". That means there can be at most one cobra in the box, and since there's at least one, there must be exactly one.

Yes, this is one of my questions. I knew that it would be a hard question when writing it but it turned out to be one of the hardest ones based on the timer stats and replies.

The same way a simple principle tested here: https://gmatclub.com/forum/m03-183621.html#p1413892 seems to be hard to grasp for many.
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22 Jul 2017, 07:32
I think this is a high-quality question and I agree with explanation.
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22 Jul 2017, 08:21
I just stumbled upon this question. Took me a while as to why S1 is the correct answer, but it was absurdly simple. Made me realise that I should start focusing more on the verbal section lol.

Nice one B.
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14 Aug 2017, 06:53
Hi Guys,

As per the question and S1:

There is at least one viper and at least one cobra in Pandora's box. How many cobras are there?
(1) From any two snakes from Pandora's box at least one is a viper.

it says that the box as at least one of the 2 snakes. So lets say the box has 10 vipes and 10 cobras = 20 snankes.
Now acc to S1 from any 2 snakes atleast one is a viper which means 1 or more than one, so in this case we can have 2 V and 0 C.

This would make the S1 insufficient.

Please let me know if my understanding of atleast 1 Viper is correct.

Ideally the question mentions only about the contents of the box so assuming there would be atleast 1 C in the box would be correct, but assuming the same for the 2 snakes would be wrong.

Please comment on this argument of mine.

Regards,
Abhishek
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14 Aug 2017, 07:19
salviabu wrote:
Hi Guys,

As per the question and S1:

There is at least one viper and at least one cobra in Pandora's box. How many cobras are there?
(1) From any two snakes from Pandora's box at least one is a viper.

it says that the box as at least one of the 2 snakes. So lets say the box has 10 vipes and 10 cobras = 20 snankes.
Now acc to S1 from any 2 snakes atleast one is a viper which means 1 or more than one, so in this case we can have 2 V and 0 C.

This would make the S1 insufficient.

Please let me know if my understanding of atleast 1 Viper is correct.

Ideally the question mentions only about the contents of the box so assuming there would be atleast 1 C in the box would be correct, but assuming the same for the 2 snakes would be wrong.

Please comment on this argument of mine.

Regards,
Abhishek

You'll benefit greatly if you read the whole discussion before posting a question. The second statement says: (1) From ANY two snakes from Pandora's box at least one is a viper.
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21 Aug 2017, 07:52
Oh! I got it!

Assuming that There are VVVVVVVVVV and (nC) in the box ; n is unknown number for now.

Whenever we pick any 2 snakes out of the box the possibility could be VV VC CV CC.

However, S1 tells us that "any 2 snakes taken out of the box will have at least 1 V"

and why is that? Because in the box C is less than 2 (n<2). Therefore, it is impossible to get CC.

Now let look back to the question states that "at least 1 C in the box" n>=1

Therefore 1<=n<2. The only answer here is 1 !!
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22 Aug 2017, 06:08
Avigano wrote:
Took me some time to get this, it's a good question.
1) FROM ANY 2 SNAKES AT LEAST 1 IS A VIPER.
>>> This means that if I have one cobra and 1 Viper I have sufficiency.
>>> What happens if I add a Cobra? So now have 2 Cobras and 1 Viper. Here it's where it gets tricky, because the question is not testing proportions, it's testing logical deduction. I have 2 cobras and 1 Viper now, if I decide to pull out 2 snakes from pandora, I can get 1 Viper and 1 Cobra OR 2 Cobras. If I get 2 Cobras I'm not only dead but I'm also not respecting the condition that AT LEAST ONE IS A VIPER.

this really helps me ..
I try to get this statement for for an hour.
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12 Sep 2017, 11:39
Hi Bunnel,

That's a wonderful question on logic. Kudos to you!
I got carried away thinking no where in the question it is mentioned that there are no other snakes in the box other than Cobras and Vipers. I was not convinced even after reading the explanation. But then realized that statement one holds true only when all but one snake are Vipers, how many types of snakes doesn't even matter. A good learning! Thanks for the question
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15 Sep 2017, 06:25
I think this is a high-quality question and I agree with explanation. Explanation provided by AdmitJA made me "get" it!

This is actually a perfect 700 question. Looks deceptively easy and at first glance, seems contrary to common sense.
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26 Sep 2017, 06:12
i am happy with statement 2 being insufficient.

so are we saying that there are 98 vipers and 1 viper?
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03 Dec 2017, 18:06
Bunuel niks18 chetan2u

I believe this this a value Q, we need to find unique answer to: how many cobras are there in a box?

Quote:
(1) Statement 1 tells us that from any two snakes from Pandora's box at least one is a viper. This may mean 1 cobra and 1 viper or 1 cobra and 99 vipers. Make sure you understand this distinction. S1 tells us that there is only 1 cobra in the box, which is sufficient.

If I got by AdmitJA logic,
Quote:
Statement 1: Any 2 snakes, possibilities ---> V, V or V, C or C, V.

I am getting zero cobra for first possibility and 1 cobra for second and third possibility.
Do we not need to have an unique answer to value Q?
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03 Dec 2017, 20:44
Bunuel niks18 chetan2u

I believe this this a value Q, we need to find unique answer to: how many cobras are there in a box?

Quote:
(1) Statement 1 tells us that from any two snakes from Pandora's box at least one is a viper. This may mean 1 cobra and 1 viper or 1 cobra and 99 vipers. Make sure you understand this distinction. S1 tells us that there is only 1 cobra in the box, which is sufficient.

If I got by AdmitJA logic,
Quote:
Statement 1: Any 2 snakes, possibilities ---> V, V or V, C or C, V.

I am getting zero cobra for first possibility and 1 cobra for second and third possibility.
Do we not need to have an unique answer to value Q?

What that user means that if from ANY two snakes from Pandora's box at least one is a viper, THESE two picked snakes (out of more than two from the box) could be VV, VC ot CV but NOT CC. It does NOT mean that there are 0 cobras. From (1) it follow that here is only 1 cobra in the box.
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16 Dec 2017, 09:26
My Take :

Statement 1:

It means there is at least 1 viper if we select any two.

So Viper count can be 1 or 2.But Cobra count cannot be 2 if we select any two.
This basically means there is only 1 Cobra.

In terms of scripts.
VC
CV
VV

But CC combination will not be possible.

Statement 2:
There are total of 99 snakes .The number of cobras not known.
So insufficient.

Kudos if it helps!!
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25 Dec 2017, 02:56
I think this is a high-quality question and I agree with explanation.
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25 Feb 2018, 20:54
I think this is a high-quality question and I agree with explanation.
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15 Apr 2018, 08:41
I think this is a poor-quality question and the explanation isn't clear enough, please elaborate. Statements in question are ambigious. To ans DS question statements must be clear.
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15 Apr 2018, 09:15
Fighter28 wrote:
I think this is a poor-quality question and the explanation isn't clear enough, please elaborate. Statements in question are ambigious. To ans DS question statements must be clear.

This question has 5 pages of discussion. That's because it's very hard. But let me assure you: the question is 100% GMAT like, unambiguous and mathematically correct. All I can suggest is to go through the discussion and read it carefully.
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16 Apr 2018, 10:11
Fighter28 wrote:
I think this is a poor-quality question and the explanation isn't clear enough, please elaborate. Statements in question are ambigious. To ans DS question statements must be clear.

Took me a couple of minutes to get it. It helped me to think about it as a probability question:
There is at least one viper and at least one cobra in Pandora's box. How many cobras are there?

(1) From any two snakes from Pandora's box at least one is a viper.
Rephrase this statement to:
You grab 2 snakes out of the box (without replacing the first snake).
The probability of grabbing two cobras is zero.
==> only one cobra in the box

Great question B!!
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31 May 2018, 18:00
I think this is a poor-quality question and I agree with explanation. Statement 1 uses ambiguous language
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31 May 2018, 23:16
dabaobao wrote:
I think this is a poor-quality question and I agree with explanation. Statement 1 uses ambiguous language

The first statement is logically, mathematically and verbally 100% correct.
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