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M07-18

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Re: M07-18  [#permalink]

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New post 06 Jun 2018, 04:00
Hi Bunuel,

I have still not able to concrete my understanding of 1st statement.
I get it minimum there would be (atleast) 1 viper. But:-
1) What is the reference of "2 snakes" here , eg- There could be 5 snakes in total and
if we pick a pair one of them would be a viper (atleast) , surely.
2) Why is following condition wrong :-
3V2C :- If we pick a pair then there could be a chance that 2C might be taken, is it because of this we have taken 1C to avoid this kind of situation.
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New post 08 Jun 2018, 03:16
luffy92 wrote:
Hi Bunuel,

I have still not able to concrete my understanding of 1st statement.
I get it minimum there would be (atleast) 1 viper. But:-
1) What is the reference of "2 snakes" here , eg- There could be 5 snakes in total and
if we pick a pair one of them would be a viper (atleast) , surely.
2) Why is following condition wrong :-
3V2C :- If we pick a pair then there could be a chance that 2C might be taken, is it because of this we have taken 1C to avoid this kind of situation.


I tried examining this many, many times on previous 5 pages.

If there are 3 vipers and 2 cobras in the box, the first statement will not be satisfied:

(1) From ANY two snakes from Pandora's box at least one is a viper.

If there are two cobras there, then we could pick two cobras and (1) will not be satisfied.
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Re: M07-18  [#permalink]

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New post 08 Jun 2018, 06:17
From any two snakes from Pandora's box at least one is a viper.
It's saying from any 2 snakes so if total no of snakes if 4, V:1 or 2 or 3 and thus C: 3 or 2 or 1 respectively
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Re: M07-18  [#permalink]

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New post 11 Jul 2018, 20:34
Bunuel wrote:
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.

(2) The total number of snakes in Pandora's box is 99.


Bunuel I did this logic and got it incorrect. Can you please help me to find out the gap?
S1: From any 2 snakes at least 1 is viper- It means probability of getting viper can be 1/2 or 1
If probability is 1/2 for viper it is 1/2 for cobra. We have to discard probability 1 since at least 1 has to be cobra. But we do not know how many snakes are there in box. It can be 98 or 2- Insufficient

S2. There are 99 snakes- InsufficienT

S1+S2= Insufficient because no has to be integer and by 99 we get decimal

Ans: E
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New post 11 Jul 2018, 20:49
Cbirole wrote:
Bunuel wrote:
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.

(2) The total number of snakes in Pandora's box is 99.


Bunuel I did this logic and got it incorrect. Can you please help me to find out the gap?
S1: From any 2 snakes at least 1 is viper- It means probability of getting viper can be 1/2 or 1
If probability is 1/2 for viper it is 1/2 for cobra. We have to discard probability 1 since at least 1 has to be cobra. But we do not know how many snakes are there in box. It can be 98 or 2- Insufficient

S2. There are 99 snakes- InsufficienT

S1+S2= Insufficient because no has to be integer and by 99 we get decimal

Ans: E


You are missing the main point. From (1) it follows that the box can have 1 cobra and any number of vipers more than or equal to 1. Please read the whole discussion. I hope it helps.
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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 M07-18  [#permalink]

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New post 01 Sep 2018, 13:28
I think this is a high-quality question and I agree with explanation.
Re M07-18 &nbs [#permalink] 01 Sep 2018, 13:28

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