For a certain set of numbers, If x is in the set, then x-3 is also in the set. If the number 1 is in the set, which of the following must also be in the set?
I. 4
II. -1
III. -5
I only
II only
III only
I and II
II and III
GMAT Question Pack Explanation: It is given that 1 is in the set. Therefore 1-3= -2 is in the set. Since we know -2 is in the set then -5 is also in the set. This set doesn't contain 4 or -1!. Therefore it is not true 4 or -1 must be in the set.
I was hoping GMAT would address an issue I found with this particular problem.
The general issue is this: The set doesn't necessarily need ANY of the numbers listed above following the logic in the answer explanation. Here is an example Let's say X = 1 and therefore the second variable x-3 would equal -2. The set could merely be (1,-2), thus the answer would be none.No where in the question does it implicitly state the set is more than 2 numbers nor does it state that it must be continuous. However, following the question and assuming that it needs to have one, I believe the better answer would be I. Was X=4, therefore X-3 = 1 so the set would have to be {4,1}
Any thoughts on this? I bought the question pack and it has been immensely helpful, so thank you; however, I just spotted this question and there has been a few questions that I have found kind of worrisome so I appreciate your response on this.
-BP
I. 4
II. -1
III. -5
I only
II only
III only
I and II
II and III
GMAT Question Pack Explanation: It is given that 1 is in the set. Therefore 1-3= -2 is in the set. Since we know -2 is in the set then -5 is also in the set. This set doesn't contain 4 or -1!. Therefore it is not true 4 or -1 must be in the set.
I was hoping GMAT would address an issue I found with this particular problem.
The general issue is this: The set doesn't necessarily need ANY of the numbers listed above following the logic in the answer explanation. Here is an example Let's say X = 1 and therefore the second variable x-3 would equal -2. The set could merely be (1,-2), thus the answer would be none.No where in the question does it implicitly state the set is more than 2 numbers nor does it state that it must be continuous. However, following the question and assuming that it needs to have one, I believe the better answer would be I. Was X=4, therefore X-3 = 1 so the set would have to be {4,1}
Any thoughts on this? I bought the question pack and it has been immensely helpful, so thank you; however, I just spotted this question and there has been a few questions that I have found kind of worrisome so I appreciate your response on this.
-BP
