{"id":13042,"date":"2012-07-18T18:17:05","date_gmt":"2012-07-19T01:17:05","guid":{"rendered":"https:\/\/gmatclub.com\/blog\/?p=13042"},"modified":"2012-07-16T15:25:14","modified_gmt":"2012-07-16T22:25:14","slug":"dont-try-to-disprove-data-sufficiency-statements-on-the-gmat","status":"publish","type":"post","link":"https:\/\/gmatclub.com\/blog\/dont-try-to-disprove-data-sufficiency-statements-on-the-gmat\/","title":{"rendered":"Don’t try to disprove Data Sufficiency statements on the GMAT"},"content":{"rendered":"

\"Knewton<\/a>\u00a0 Rich is one of the stellar teachers in Knewton\u2019s<\/em>\u00a0<\/em>GMAT course<\/em><\/a>, in whch he loves helping students rock the Quantitative section.<\/em><\/p>\n

 <\/p>\n

In any\u00a0GMAT prep<\/a>\u00a0course, one of the first things taught about the Data Sufficiency section is that\u00a0the two statements are true and do not contradict one another<\/em>.\u00a0 It\u2019s a point that\u2019s easy to gloss over and completely overlook during the hustle and bustle of your test prep.<\/p>\n

But this supposedly self-evident point gets many students into trouble when dealing with YES\/NO questions, because they mistakenly try to prove or disprove\u00a0the statements<\/em>\u00a0rather than\u00a0the prompt<\/em>.<\/p>\n

I\u2019ll explain:\u00a0 Recall that a YES\/NO question is one in which the answer will be \u201cYes\u201d or \u201cNo.\u201d\u00a0 For example, \u201cIs x even?\u201d or \u201cAre the distances equal?\u201d\u00a0 This is in contrast to VALUE questions, for which you must come up with one particular value (e.g. \u201cWhat is x?\u201d, \u201cWhat is the average of a and b?\u201d).<\/p>\n

If a statement produces both a YES and a NO, then it is insufficient.\u00a0 If the statement (or combination of statements) always produces a YES or always produces a NO, then it is sufficient.\u00a0 (Remember, a NO is not the same thing as INSUFFICIENT; so if you\u2019re asked \u201cIs x even?\u201d and a statement lets you know that x is always odd, then that is SUFFICIENT, because you can answer NO with certainty.)<\/p>\n

Basic example:<\/p>\n

Is x odd?<\/p>\n

(1)\u00a0 x is a multiple of 3.<\/p>\n

(2)\u00a0 x is a multiple of 5.<\/p>\n

For Statement (1), x could be 3, which would lead to a YES, but x could also be 6, which would lead to a NO.\u00a0 Insufficient.<\/p>\n

For Statement (2), x could be 5, which would lead to a YES, but x could also be 10, which would lead to a NO.\u00a0 Also insufficient.<\/p>\n

Combining the statements, we see that x could be 15, which would lead to a YES, but x could also be 30, which would lead to a NO.\u00a0\u00a0 Final answer, E: the statements together are not sufficient to answer the question.<\/p>\n

This is a simple example that would not likely appear on the GMAT, but it\u2019s great for illustrating a basic mistake students make: trying to disprove the statements.<\/p>\n

It might be tempting to look at Statement (1) and try to find a YES or a NO\u00a0to the statement itself<\/em>, rather than the prompt.\u00a0 So you try to prove\/disprove \u201cx is a multiple of 3\u2033, rather than prove\/disprove the real question, \u201cIs x odd?\u201d<\/p>\n

This would result in you picking, let\u2019s say, x = 3, because it answers YES to \u201cx is a multiple of 3\u2033.\u00a0 Then you might pick x = 5, because it answers NO to \u201cx is a multiple of 3.\u201d<\/p>\n

But of course, both 3 and 5 answer YES to the question in the prompt, and you may erroneously conclude that Statement (1) is sufficient, when in actuality, it is not.<\/p>\n

Obviously, this approach can get you into trouble, because you may get an incorrect answer.\u00a0 But there\u2019s an even more basic error behind this mistake:\u00a0 You\u2019re wasting valuable time trying to prove\/disprove something\u00a0that is already known to be true<\/em>!<\/p>\n

And thus I return to that basic maxim of Data Sufficiency questions:<\/p>\n

The statements are\u00a0always true<\/em>\u00a0and\u00a0never contradict one another<\/em>.\u00a0 Again, it seems like a trivial point, but as the aforementioned example demonstrates, you\u2019d be surprised how forgetting the basics can lead to unnecessary wasted time!<\/p>\n

So, in conclusion, recognize that the statements are true, and use their information to address what really matters:\u00a0 the question in the prompt.<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00a0 Rich is one of the stellar teachers in Knewton\u2019s\u00a0GMAT course, in whch he loves helping students rock the Quantitative section.   In any\u00a0GMAT prep\u00a0course, one of the first things…<\/p>\n","protected":false},"author":104,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,243,718,736],"tags":[],"class_list":["post-13042","post","type-post","status-publish","format-standard","hentry","category-gmat","category-blog","category-data-sufficiency-gmat","category-quant-gmat","entry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/posts\/13042","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/users\/104"}],"replies":[{"embeddable":true,"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/comments?post=13042"}],"version-history":[{"count":2,"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/posts\/13042\/revisions"}],"predecessor-version":[{"id":13045,"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/posts\/13042\/revisions\/13045"}],"wp:attachment":[{"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/media?parent=13042"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/categories?post=13042"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gmatclub.com\/blog\/wp-json\/wp\/v2\/tags?post=13042"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}