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risingstar
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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 06:11
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does z = 8?

(1) z = 2 or z = 8
(2) z = 3 or z = 8

e

(1) z = 2 or z = 8
(2) z = 8

b

(1) z = 3 or z = 6
(2) z = 8

d

(1) z = 9 or z = 3
(2) z = 9 or z = 8

a

I'm trying to understand the answer format. Is it appropriate to AND 1 and 2 when neither is sufficient alone? Thanks for feedback.



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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 09:14
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does z = 8?

(1) z = 2 or z = 8
(2) z = 3 or z = 8

it should be c, both together are sufficient?
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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 12:41
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I still think the answer is E.

because when we combine we are saying each statement is true and it means z=8 or z=2 or z= 3, we still cannot say if z=8 or not, in once case it is =8 and in 2 others its not. hence E
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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 13:45
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The questions below are Yes/No type of DS problems. If you are able to answer the q yes or no, with the help of either of statement or both, it's sufficient.

Does z = 8?

(1) z = 2 or z = 8
(2) z = 3 or z = 8

Answer: C (z=8): from (1) you have that z is either 2 or 8; from (2) either 3 or 8. Intersection of these statements gives unique value for z, which is 8. When the answer is C it means that two statements together are sufficient to determine the answer.


(1) z = 2 or z = 8
(2) z = 8

Answer: B. (z=8)


(1) z = 3 or z = 6
(2) z = 8

Answer: D?. This type of question WILL NEVER OCCUR in real GMAT test. Remember in DS statements (1) and (2) NEVER contradict. Here (2) gives us the unique value for z, BUT (1) says that z=2 or z=6, they clearly contradict: from (1) you get that z is not equal to 8, and from (2) you get that z equals to 8.

Difference with the first question (answer C) is following: in that case our answer z=8 doesn't contradict with either of statements, (1) is saying that z is either 2 or 8 and (2) either 3 or 8. So, our answer z=8 doesn't contradict.


(1) z = 9 or z = 3
(2) z = 9 or z = 8

Answer: A (z doesn't equal to 8)
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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 15:04
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Does z = 8?

(1) z = 2 or z = 8
(2) z = 3 or z = 8

Answer: C (z=8): from (1) you have that z is either 2 or 8; from (2) either 3 or 8. Intersection of these statements gives unique value for z, which is 8. When the answer is C it means that two statements together are sufficient to determine the answer.

Bunuel, I think answer is E

because even when we consider S1 and S2, all we know is z=2 or 3 or 8, not a single value of 8 for sure.
Why do we consider intersecting the S1 and S2 ? we do union all the time (that is take information from both).

I think this cannot be a GMAT question, if it is, the answer has to be E. please elaborate why intersection, why not union - thanks
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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 17:06
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srini123
Does z = 8?

(1) z = 2 or z = 8
(2) z = 3 or z = 8

Answer: C (z=8): from (1) you have that z is either 2 or 8; from (2) either 3 or 8. Intersection of these statements gives unique value for z, which is 8. When the answer is C it means that two statements together are sufficient to determine the answer.

Bunuel, I think answer is E

because even when we consider S1 and S2, all we know is z=2 or 3 or 8, not a single value of 8 for sure.
Why do we consider intersecting the S1 and S2 ? we do union all the time (that is take information from both).

I think this cannot be a GMAT question, if it is, the answer has to be E. please elaborate why intersection, why not union - thanks
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I believe the 2nd and fourth answer is clear. As already said, the 3rd is contradictory.

For the first one, I believe it should be C.

Think of these as the equation of two straight lines. The first one is (z-2)(z-8)=0 (or z^2-10z-24=0) and the second one is (z-3)(z-8)=0 (or z^2-11z-24=0), individually these are insufficient but together there is only one common point 8, hence the answer is C.
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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 18:06
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srini123
Does z = 8?

(1) z = 2 or z = 8
(2) z = 3 or z = 8

Answer: C (z=8): from (1) you have that z is either 2 or 8; from (2) either 3 or 8. Intersection of these statements gives unique value for z, which is 8. When the answer is C it means that two statements together are sufficient to determine the answer.

Bunuel, I think answer is E

because even when we consider S1 and S2, all we know is z=2 or 3 or 8, not a single value of 8 for sure.
Why do we consider intersecting the S1 and S2 ? we do union all the time (that is take information from both).

I think this cannot be a GMAT question, if it is, the answer has to be E. please elaborate why intersection, why not union - thanks
Show more

It is certainly not a very GMAT-like question, but the answer is certainly C. From Statement 1, we know that z is either 2 or 8. Could z be 2? Well, from Statement 2, we know z is either 3 or 8. So clearly z is not 2. That only leaves one value for z -- 8.
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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 18:26
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srini123
Does z = 8?

(1) z = 2 or z = 8
(2) z = 3 or z = 8

Answer: C (z=8): from (1) you have that z is either 2 or 8; from (2) either 3 or 8. Intersection of these statements gives unique value for z, which is 8. When the answer is C it means that two statements together are sufficient to determine the answer.

Bunuel, I think answer is E

because even when we consider S1 and S2, all we know is z=2 or 3 or 8, not a single value of 8 for sure.
Why do we consider intersecting the S1 and S2 ? we do union all the time (that is take information from both).

I think this cannot be a GMAT question, if it is, the answer has to be E. please elaborate why intersection, why not union - thanks

It is certainly not a very GMAT-like question, but the answer is certainly C. From Statement 1, we know that z is either 2 or 8. Could z be 2? Well, from Statement 2, we know z is either 3 or 8. So clearly z is not 2. That only leaves one value for z -- 8.
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Thanks for the explanation. I'll use this logic when I combine S1 and S2 for my GMAT.
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does z = 8? (1) z = 2 or z = 8 (2) z = 3 or z = 8 e (1) z = 23 Oct 2009, 19:04
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I got them from a Kaplan book. I didn't know why they used them, but now I understand they simply illustrate how ds answer choices should be construed.

That is, if neither stmt 1 or 2 alone can be used to answer the question, see if their intersection can give a sufficient answer.



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Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
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