izzai Posted June 5, 2012 Share Posted June 5, 2012 Is X an integer? 1. X/2 is an integer 2.2x is an integer. The answer is A. I'm confused because the book states that according to 1, X would be an even integer and so that should make it sufficient. But why would that be true if when X=1, X/2=1/2? Or am I approaching it the wrong way? Quote Link to comment Share on other sites More sharing options...
eagleeye Posted June 8, 2012 Share Posted June 8, 2012 izzai: you are reading it the wrong way. 1. says X/2 is an integer that means X/2 = 1 or 2 or 3 etc. so X =2,4,6 etc. You can't assume X=1 because, they say X/2 is an integer which means X is even. Let me know if this helps :) Quote Link to comment Share on other sites More sharing options...
izzai Posted June 11, 2012 Author Share Posted June 11, 2012 It does! Thank you! Quote Link to comment Share on other sites More sharing options...
HhjDubai Posted August 14, 2012 Share Posted August 14, 2012 Agree with a Put in x= 1,1/2,3/2,2, only first statement satisfies Quote Link to comment Share on other sites More sharing options...
BGPC Eliza Posted November 20, 2014 Share Posted November 20, 2014 (edited) yes it is important to make sure that you are clear about what the question is asking. Here (1) says that x divided by two is an integer, this means that x has to be an integer because it must be an even integer to mean that x/2 is an integer. (2) says that x multiplied by 2 is an integer that means that x could be an integer, like 1 or that it could not be like 1/2 Edited November 21, 2014 by BGPC Eliza Quote Link to comment Share on other sites More sharing options...
Brent Hanneson Posted November 21, 2014 Share Posted November 21, 2014 Is x an integer? 1) x/2 is an integer 2) 2x is an integer. Target question:Is x an integer? Statement 1: x/2 is an integer In other words, x/2 = k, where k is an integer Multiply both sides by 2 to get: x = 2k In other words, x = (2)(some integer k) If k is an integer, then x is an integer (an EVEN integer at that) Since we can answer the target question with certainty, statement 1 is SUFFICIENT Statement 2: 2x is an integer There are several values of x that satisfy this condition. Here are two conflicting cases: Case a: x = 1, in which case 2x = 2(1) = 2, and 2 is an integer. In this case, x IS an integer Case b: x = 1.5, in which case 2x = 2(1.5) = 3, and 3 is an integer. In this case, x is NOT an integer Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT Answer = A Cheers, Brent Quote Link to comment Share on other sites More sharing options...
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