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15 Sep 2014, 23:35
Official Solution: This is a hard question that challenges testtaker's logic. It is simple once you understand it but hard if you have never solved it. If you made a mistake on this question, make sure you understand the logic so you can be armed with this new tool for the real test. (1) Statement 1 tells us that from any two snakes from Pandora's box at least one is a viper. This does not mean that there are 2 snakes in the box or that there is only 1 viper. Instead, it indicates that at most, there is 1 cobra. 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. (2) The total number of snakes Pandora's box is 99. Clearly insufficient. Answer: A
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Re: M0718
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15 Oct 2014, 11:04
Bunuel wrote: Official Solution:
(1) From any two snakes from Pandora's box at least one is a viper. Since from ANY two snakes one is a viper then there cannot be 2 (or more) cobras and since there is at least one cobra then there must be exactly one cobra in the box. Sufficient. (2) The total number of snakes Pandora's box is 99. Clearly insufficient.
Answer: A Hi Bunuel, Any specific types/patterns of word problems that you could suggest here. Facing a lot of time issues especially when these word problems come in DS mode.



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Re: M0718
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09 Nov 2014, 15:26
Bunuel wrote: Official Solution:
(1) From any two snakes from Pandora's box at least one is a viper. Since from ANY two snakes one is a viper then there cannot be 2 (or more) cobras and since there is at least one cobra then there must be exactly one cobra in the box. Sufficient. (2) The total number of snakes Pandora's box is 99. Clearly insufficient.
Answer: A Hi Please do reply From any two snakes from Pandora's box at least one is a viperdoes not it mean that if 2 snakes were taken out from the box at least one is viper if you consider this will the answer be different



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10 Nov 2014, 02:14
Bunuel wrote: shyam593 wrote: Bunuel wrote: Official Solution:
(1) From any two snakes from Pandora's box at least one is a viper. Since from ANY two snakes one is a viper then there cannot be 2 (or more) cobras and since there is at least one cobra then there must be exactly one cobra in the box. Sufficient. (2) The total number of snakes Pandora's box is 99. Clearly insufficient.
Answer: A Hi Please do reply From any two snakes from Pandora's box at least one is a viperdoes not it mean that if 2 snakes were taken out from the box at least one is viper if you consider this will the answer be different Yes, it means exactly that. But what do you mean that the answer would be different? Sorry got it now irrespective of the no of vipers, cobra can never be more than 1.



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24 Nov 2014, 08:34
Yes but we do know know how many snakes there are in the box.
For example if the number of snakes is 10 there could be 9 ; 1 or it could be 5;5.
Second one is clearly insufficient also
And both are insufficient.
99 Snakes 1 cobra 98 vipers, or 97/2
Please explain
Thank you



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24 Nov 2014, 09:17
It took me sometime to understand statement 1 in the test. For those having trouble like me, hope this helps! Statement 1: Any 2 snakes, possibilities > V, V or V, C or C, V. There is no possibility for C, C. This means that there is only 1 cobra in the box. Sufficient. Statement 2: Totally irrelevant and useless.
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25 Dec 2014, 23:35
Bunuel wrote: Princas1 wrote: Yes but we do know know how many snakes there are in the box.
For example if the number of snakes is 10 there could be 9 ; 1 or it could be 5;5.
Second one is clearly insufficient also
And both are insufficient.
99 Snakes 1 cobra 98 vipers, or 97/2
Please explain
Thank you Let me ask you if there are 5 vipers and 5 cobras, would the second statement be correct? Hey Bunuel, it's still not clear for me concerning answer (1). If we take your example with 10 snakes, doesn't it mean that we can have anything from (5V 5C; 6V 4C;...9V 1C) according to statement 1? A ratio of 6:4 V to C is still "at least 1 viper" for any 2 snakes. Thanks for clarifying.
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26 Dec 2014, 06:59
TudorM wrote: Bunuel wrote: Princas1 wrote: Yes but we do know know how many snakes there are in the box.
For example if the number of snakes is 10 there could be 9 ; 1 or it could be 5;5.
Second one is clearly insufficient also
And both are insufficient.
99 Snakes 1 cobra 98 vipers, or 97/2
Please explain
Thank you Let me ask you if there are 5 vipers and 5 cobras, would the second statement be correct? Hey Bunuel, it's still not clear for me concerning answer (1). If we take your example with 10 snakes, doesn't it mean that we can have anything from (5V 5C; 6V 4C;...9V 1C) according to statement 1? A ratio of 6:4 V to C is still "at least 1 viper" for any 2 snakes. Thanks for clarifying. NO. We cannot have more than 1 cobras. If there are 5 cobras and 5 vipers then the first statement will NOT hold. (1) says from ANY two snakes from Pandora's box at least one is a viper. If there are 5 cobras and 5 vipers then we could have two snakes from which BOTH are vipers.
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Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
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Re: M0718
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20 Jan 2015, 19:57
i see the goal here (trickery), but the question wording is wrong.
Implication of "any" two snakes is that there are more than 1 pair, otherwise proper english would be "the" two snakes.
This one should be dumped from the question bank.



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21 Jan 2015, 00:04



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02 Mar 2015, 17:14
Excellent question, but I'm partial because I got it right. It's more representative of the type of thinking on the verbal portion of the exam, IMO, which is another reason I like it, and it also reminded me of the Monty Hall problem for whatever reason.



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16 Mar 2015, 03:58
this is a good question.
To people who are still confused about the 1st statement the below example should help you.
Ex:
Stated in the question There is at least one viper and at least one cobra in Pandora's box
Statement 1 From any two snakes from Pandora's box at least one is a viper.
Cases that are in scope and are correct are 1V 1C is correct 2V 1C is correct 3V 1C is correct . . . n1V 1C is correct where n >0 and n is an integer
Here the no of cobras are always one because in the question it is stated that there is at least one cobra in Pandora's box. So minimum value of no of cobras is 1
Note: Cases that are out of scope. 1V 2C 2V 2C 3V 3C etc...
Notice the no of cobras is always greater one . But what does the statement 1 say "from any two snakes at least one is a viper." So all the above cases are out of scope as there is a chance that from any two snakes none can be a viper.
Hope this helps.



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Re: M0718
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27 May 2015, 15:34
At least one is a Viper > Couldn't there be two vipers  and therefore 0 cobras  and invalidate statement 1? Thanks.



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27 May 2015, 16:27
Look at the question. The condition u mentioned is out of scope. The question clearly says that there is atleast one V and one C in the box. You should not consider the case where cobras are 0.
When only the condition in the question is considered
Possible cases are 1v 1c 2v 2c Etc
Cases that are out of scope 1v 0c 2v 0c 3v 0c . . . Nv 0c 0v 1c 0v 2c 0v 3c . . . 0v Nc



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10 Jun 2015, 18:55
Bunuel wrote: KPMM07 wrote: I think this question is poor and not helpful. Please elaborate on this. The question is perfectly valid, though quite hard. Interesting solution, but not sure how this is math (not counting/probability/algebra/arithmetic etc.) More like it was a question testing your logical deduction.



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23 Sep 2015, 11:22
I think this is a poorquality question and the explanation isn't clear enough, please elaborate.



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