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­Probability of neither can be given by 1-(atleast 1)
P(atleast 1) = P(exactly 1) + P(Both)

Statement 1: Gives us probability of only exactly one
so, Insufficient

Statement 2: Gives us proability of only both
so, alone is insufficient

Together both statements gives us probabilty to solve the eqn

IMO C
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​Now we know that,

P(A∪B)=P(A)+P(B)−P(A∩B)
The probability that the mouse finds only one of the treats is:
P(only one)=P(A∪B)−P(A∩B)
And the probability that the mouse finds neither is P(neither)=1−P(A∪B)

Therefore we need to find p(AUB) to get P(Neither).

With Statement one:
The probability that the mouse will find only one of the two treats is 1/5. (i.e P(only one))

With statement two:
The probability that the mouse will find both treats is 3/10. (i.e P(A∩B)).

Hence, we need both the statements as with single statement we cant solve the equation. Hence C.
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Statement (1): The probability that the mouse finds only one of the two treats is 1/5.
This means: P(only one)=P(A∪B)−P(A∩B)=1/5
However, we only know P(A∪B)−P(A∩B), not their individual values. Thus, we cannot determine P(A∪B) or P(neither) directly.​

Statement (2): The probability that the mouse finds both treats is P(AnB)=3/10
but without P(A) or P(B) or P(A∪B), we cannot determine P(neither).

Combining both.
P(A∪B)= 1/5+3/10 = 1/2
P(neither) = `1 - P(A∪B) = 1/2

The correct answer is: C
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1) P(1) + P(2) is given. Insuff
2) P (both) is given. Insuff

Using above statements answer can be found. Hence C
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­I. 1-(1/5)-P(both) = 4/5- P(both) INSUFFICIENT
II. P(both) = 3/10 INSUFFICIENT
(Both) II fills the missing piece required by I SUFFICIENT
C is correct.
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Total Probabolity= 1 = Only A+Only B+Both+Neither
1. Only of the treat = 3/10..so, only A+only B =3/10...Both not given... Insufficient

2. Both treat = 1/5..But no details of A & B..Insufficient

Together,
only A+only B = 3/10
both = 1/5

so 1 = 3/10  +  1/5  + none
none= 1/2

Answer C
 
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Let's consider the two events A and B, where A : The mouse find the 1st treat and B : The mouse find the 2nd treat.
We're looking fot the probability that the mouse will find neither of the treats?
So we're looking ( in a mathematical language) for : NO(A) and NO(B) meaning that if we found A or B then we're going to use : 1- Pr(A or B)* to find the probability of NO(A) and NO(B).


(1) The probability that the mouse will find only one of the two treats is 1/5.
in this case we have Pr(A) only or Pr(B) only,
Actually to apply * we need the probability also of selecting A and B, because, probability of finding one treat A or B, in the probability of A + probability of B + probability of BOTH (which we do not know
Not sufficient,


(2) The probability that the mouse will find both treats is 3/10.
Clearly not sufficient, because we need the probability of finding A or B

Combining both 1 and 2, it is sufficieint because, applying * we're going to have 1-3/10-1/5=1/2

Correct answer is C
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Bunuel
­In a science experiment, a mouse is placed in a labyrinth with two different treats hidden in it. What is the probability that the mouse will find neither of the treats?

(1) The probability that the mouse will find only one of the two treats is 1/5.
(2) The probability that the mouse will find both treats is 3/10.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked.
C. BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient to answer the question asked.
D. EACH statement ALONE is sufficient to answer the question asked.
E. Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

 


This question was provided by GMAT Club
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­
 ­

(1) i only now about 1 or the other
(2) i only know abou both together

(1)+(2) i know the probability it finds 1 or the other or both

Posted from my mobile device
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Given - ­In a science experiment, a mouse is placed in a labyrinth with two different (consider them as A and B) treats hidden in it.

To find - What is the probability that the mouse will find neither of the treats?

Let, P(A) and P(B) are the probabilities for finding first treat and second treat respectively. 
So, value of probability that the mouse will find neither of the treats i.e. P(AUB)'
and that we calculate by using below formula.
\(P(AUB) + P(AUB)' = 1\)  -------Eq1
1st - The probability that the mouse will find only one of the two treats is 1/5.
P(A∩B') = A only = P(A) - P(A∩B) Similarly P(B∩A') = B only = P(B) - P(A∩B)
P(A∩B') + P(B∩A') = \(\frac{1}{5}\) 
P(A∩B') + P(B∩A') = P(A) + P(B) - 2 * P(A∩B) = \(\frac{1}{5}\)­
But, P(AUB) = P(A) + P(B) - P(A∩B)
Therefore,
P(A∩B') + P(B∩A')= P(AUB) - P(A∩B) = \(\frac{1}{5}\)­ -------Eq2
Nothing else we can deduced from this instruction to get the value of probability that the mouse will find neither of the treats i.e. P(AUB)'
Not sufficient.

2nd - The probability that the mouse will find both treats is 3/10.
That is P(A∩B) = \(\frac{3}{10}\) Nothing else so Not sufficient.

Now combining both from equation 2 and P(A∩B) = \(\frac{3}{10}\)­
P(AUB) - \(\frac{3}{10}\)­ = \(\frac{1}{5}\)­
P(AUB) = \(\frac{1}{5}\)­ + \(\frac{3}{10}\)­
P(AUB) = \(\frac{1}{2}\)­
Now substituting this value in equation 1 

P(AUB)' = 1 - \(\frac{1}{2}\)­
\(P(AUB)'\) = \(\frac{1}{2}\)­ That is the probability that the mouse will find neither of the treats. 
Answer is C.
­
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Bunuel
­In a science experiment, a mouse is placed in a labyrinth with two different treats hidden in it. What is the probability that the mouse will find neither of the treats?

(1) The probability that the mouse will find only one of the two treats is 1/5.
(2) The probability that the mouse will find both treats is 3/10.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked.
C. BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient to answer the question asked.
D. EACH statement ALONE is sufficient to answer the question asked.
E. Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

 


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­
 ­
­Probability for neither of the treats=1-finding one treat-finding both the treats
for this both statements are required
Answer is C
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Bunuel
­In a science experiment, a mouse is placed in a labyrinth with two different treats hidden in it. What is the probability that the mouse will find neither of the treats?

(1) The probability that the mouse will find only one of the two treats is 1/5.
(2) The probability that the mouse will find both treats is 3/10.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked.
C. BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient to answer the question asked.
D. EACH statement ALONE is sufficient to answer the question asked.
E. Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

 


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­
 ­
Two different treats hidden in labyrinth, lets say A and B
Prob that mouse will find neither of the treats?

Option1: Prob that the mouse will find only one of the two treats is 1/5
i.e P(A) =1/5 or P(B)=1/5
Possibility=1= Aonly  + Bonly + both (A & B) + neither (A and B)
With this we cannot infer neither (A and B)

Option2:The probability that the mouse will find both treats is 3/10
Prob( A & B) = 3/10
but we do not know what is probability of finding A or B

Considering both 
1= 1/5+1/5+3/10+ neither (A and B)
1=7/10 + neither (A and B)
neither ( A and B) = 3/10

So C is the answer



 
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C is my answer.

Combining , the probabilty the mouse will find either of treats = 1/5 + 3/10 = 1/2

Hence , the probability that the mouse will find neither of the treats = 1 - 1/2 = 1/2
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Total Probability = 1 = P(Finding both treats) + P(Finding only 1 Treat) + P(Finding none of the treats)
Need to find P(Finding none of the treats)

Statement 1 only gives us P(Finding only 1 Treat) - Not sufficient
Statement 2 only gives us P(Finding both treats) - Not sufficient

Combining both is Sufficient

Answer C
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­In a science experiment, a mouse is placed in a labyrinth with two different treats hidden in it. What is the probability that the mouse will find neither of the treats?

P (neither)=1- (P(A)+P(B)-P(A and B)) or 1-( P(A only)+P(B only)+ P(A and B only))

(1) The probability that the mouse will find only one of the two treats is 1/5.- Since we dont know whether events are dep or indep and their individual prob hence we cant find prob of both. NS
(2) The probability that the mouse will find both treats is 3/10.- We have no info on P of exactly one of the treats hence NS

Combined- We have all the required info hence suff

Ans C
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­In a science experiment, a mouse is placed in a labyrinth with two different treats hidden in it. What is the probability that the mouse will find neither of the treats?
P( FIND ONLY T2)=X
P(FIND ONLY T2)=Y
P( FIND TQ AND T2)=M
P(NETHER FIND T1 AND T2)=N

X+Y+M+N=1
N=1-X-Y-M (EQ1)

(1) The probability that the mouse will find only one of the two treats is 1/5.

X+Y=1/5
substitute in EQ1
N=1-X-Y-M = 1-(X+Y)-M
N= 1-1/5-M
N= 4/5-M
NOT SUFFICIENT

(2) The probability that the mouse will find both treats is 3/10.
M= 3/10
substitute in EQ1
N=1-X-Y-M = 1-(X+Y)-M
N= 1-(X+Y)-3/10
N=7/10-(X+Y)
NOT SUFFICIENT

Together 1 and 2
X+Y=1/5
M= 3/10
substitute in EQ1
N=1-X-Y-M = 1-(X+Y)-M=1-(1/5)-(3/10)= 1/2

SUFFICIENT


ANS
LETTER C
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Bunuel
­In a science experiment, a mouse is placed in a labyrinth with two different treats hidden in it. What is the probability that the mouse will find neither of the treats?

(1) The probability that the mouse will find only one of the two treats is 1/5.
(2) The probability that the mouse will find both treats is 3/10.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient to answer the question asked.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient to answer the question asked.
C. BOTH statements (1) and (2) TOGETHER are sufficient to answer the question asked, but NEITHER statement ALONE is sufficient to answer the question asked.
D. EACH statement ALONE is sufficient to answer the question asked.
E. Statements (1) and (2) TOGETHER are NOT sufficient to answer the question asked, and additional data specific to the problem are needed.

 


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 ­
­I feel that the answer should be B since we can find the prob of not finding both by 
1-3/10
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