![\"Manhattan](\"\/\/www.manhattanprep.com\/gre\/wp-content\/uploads\/sites\/19\/2016\/03\/blog-grequantpen.png\")
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Did you know that you can attend the first session of any of our online or in-person GRE\u00a0courses absolutely free? We\u2019re not kidding! Check out our upcoming courses here<\/a>.<\/em><\/strong><\/p>\n Let’s do a GRE Discrete Quant experiment. This is one I do with all of my GRE classes and tutoring students. Grab a piece of paper, a pen, and a stopwatch (or use the stopwatch function on your mobile device).<\/p>\n When you\u2019re ready, click \u201cstart\u201d on the stopwatch and begin the following multiple-choice GRE Discrete Quant problem\u2026<\/p>\n Solution A contains 20% alcohol by volume, and Solution B contains 50% alcohol by volume. If the two solutions are combined, the resulting mixture of A and B contains 32% alcohol by volume. What percent of the total volume of the mixture is Solution A?<\/p>\n (A) 35% Okay, write down the answer you got and how much time it took you.<\/p>\n Right now, though, I\u2019m not interested in what answer you got. I just want to know two things:<\/p>\n Believe it or not, there is probably an inverse correlation<\/em> between those two answers. Students who dive in and start writing equations right away will often spend 2:30 to 3:30 on a question like this\u2014generally much longer than students who take their time before writing things down. They\u2019re also much more likely to get the question wrong!<\/p>\n Savvy test takers don\u2019t dive in and start solving right away. They know that slowing down at first (even though it seems counter-intuitive) can improve both timing and accuracy.<\/p>\n The savvy<\/em> way to approach GRE Discrete Quant questions is this:<\/p>\n It\u2019s not Reading Comprehension, so you don\u2019t need to take notes! If you\u2019re writing while you\u2019re reading, you\u2019re much more likely to miss key pieces of information. Think about the concept that\u2019s being tested, and what information the problem is giving you.<\/p>\n Here\u2019s what I\u2019d be thinking while reading the problem above: \u201cOkay, this is a weighted average problem\u2014we\u2019re mixing two things together. They\u2019re each different amounts of alcohol, and then we\u2019re given a total.\u201d<\/p>\n Again, before writing equations down, just define the question. Is it asking us for a value, a sum, a difference, a proportion, a variable \u201cin terms of\u201d another variable, etc.?<\/p>\n This is the best way to ensure that you don\u2019t accidentally solve for the wrong thing! The GRE loves to trick us into doing that. How many times have you looked back to realize that your algebra was correct, but you just answered the wrong question?<\/p>\n My thoughts: \u201cThe question is asking me about A as a percentage of the total <\/em>of A and B. I bet they\u2019ll include a trap if I accidentally solve for B!\u201d<\/p>\n Before picking up the pen, do a common sense test <\/em>first! This isn\u2019t high school, where you have to show all of your work before picking an answer. Think of the answers as part of the problem itself!<\/p>\n Scanning the answers first can give you powerful clues for how to solve a multiple-choice problem. For example, if a geometry problem featured \u221a3 in some of the answer choices, that\u2019s your clue to think about 30:60:90 right triangles. If a ratio problem featured some ratios that were greater than 1 (e.g. 3:2) and some that were less than 1 (2:3), that\u2019s your clue to assess which portion should be greater.<\/p>\n My thoughts on the problem above: \u201cI notice that some of the answer choices are less than 50%, one is 50%, and the others are greater than 50%. If I can just figure out whether I have more A or more B in the mixture, I can narrow it down.\u201d<\/p>\n \u201cSince the 32% in the overall mixture is closer to A\u2019s 20% than B\u2019s 50%, that means that A must make up more of the overall mixture\u2014in other words, more than 50%. I can eliminate (A), (B), and (C).\u201d<\/p>\n As I mentioned before, the GRE loves to set traps for us. If you become aware of those traps, you can narrow down answer choices easily. Here are some common traps to watch out for:<\/p>\n If we eliminate all of the likely trap answers, that just leaves us with (D).<\/p>\n In a situation like this, the best strategic move would be to pick (D) and move on. It\u2019s a bad idea to get bogged down in a lot of algebra just to prove what you probably already know to be true. The savvy test-taker would say, \u201c90% sure of my answer in 40 seconds is better than 100% sure of my answer in 3 minutes.\u201d<\/p>\n It\u2019s an uncomfortable feeling not to know for sure, but the GRE is a time-constrained game! You don\u2019t have time to be 100% sure of every answer.<\/strong><\/p>\n If this question were different, and you weren\u2019t able to eliminate all of the other answer choices, you would want to make a strategic<\/em> decision about which approach would work best. Don\u2019t just dive into doing algebra! Remember that there are other strategies that can often be faster: picking smart numbers, working backwards from answer choices, estimating, etc.<\/p>\n On this problem, if <\/em>we wanted to solve, we could do a combination of strategies. Since we don\u2019t have any concrete amounts given, we can pick our own numbers. Let\u2019s say that the total mixture is 100 liters.<\/p>\n We could also work backwards from the answer choices, based on that 100L total. Since we suspect that the answer is (D), let\u2019s then say A = 60 liters. The amount of alcohol in A would be 20% of 60, so 12L. If A is 60L, then B must be 40L. 50% of 40L would be 20L of alcohol. Thus the total amount of alcohol is 12 + 20 = 32 liters of alcohol out of 100 \u00e0 32%.<\/p>\n That works! So (D) must be the right answer.<\/p>\n If you did long or complicated algebra on this question, you probably took well over 2 minutes to solve. It\u2019s also far<\/em> more likely that you got the answer wrong! Putting the pen down and thinking through the problem in the way we outlined above will improve both your timing and your accuracy.<\/p>\n The next time you\u2019re doing a set of GRE Discrete Quant problems, write this on a post-it note and keep it next to you as you\u2019re working:<\/p>\n Good luck!\u00a0?<\/em><\/strong><\/p>\n Want more guidance from our GRE gurus? You can attend the first session of any of our online or in-person GRE\u00a0courses absolutely free! We\u2019re not kidding.\u00a0Check out our upcoming courses here<\/a>.\u00a0<\/em><\/strong><\/p>\n Did you know that you can attend the first session of any of our online or in-person GRE\u00a0courses absolutely free? We\u2019re not kidding! Check out our upcoming courses here. Let’s do a GRE Discrete Quant experiment. This is one I do with all of my GRE classes and tutoring students. Grab a piece of paper, […]<\/p>\n","protected":false},"author":28,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2,474284,921840,421,6,7,9,733445,154333],"tags":[184144,1362494,184145],"yst_prominent_words":[],"class_list":["post-8914","post","type-post","status-publish","format-standard","hentry","category-challenge-problems","category-current-studiers","category-gre-prep-2","category-gre-quant-2","category-gre-strategies","category-how-to-study","category-math-gre-strategies","category-study-tips-2","category-taking-the-gre-2","tag-discrete-math","tag-discrete-quant","tag-put-the-pen-down"],"_links":{"self":[{"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/posts\/8914","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/users\/28"}],"replies":[{"embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/comments?post=8914"}],"version-history":[{"count":8,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/posts\/8914\/revisions"}],"predecessor-version":[{"id":10946,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/posts\/8914\/revisions\/10946"}],"wp:attachment":[{"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/media?parent=8914"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/categories?post=8914"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/tags?post=8914"},{"taxonomy":"yst_prominent_words","embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/yst_prominent_words?post=8914"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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\n(B) 40%
\n(C) 50%
\n(D) 60%
\n(E) 70%<\/p>\n\n
1. Read the entire problem, pen down.<\/strong><\/h4>\n
2. Define what the question is asking for.<\/strong><\/h4>\n
3. Scan the answers and try to eliminate.<\/strong><\/h4>\n
4. Look out for traps.<\/strong><\/h4>\n
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5. Be strategic.<\/strong><\/h4>\n
Saving Time on GRE Discrete Quant<\/strong><\/h4>\n
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\n![\"ceilidh-erickson-Manhattan-Prep-GMAT-Instructor\"](\"\/\/d27gmszdzgfpo3.cloudfront.net\/gmat\/wp-content\/uploads\/sites\/18\/2016\/02\/ceilidh-erickson-150x150.png\" "\\"Ceilidh")
<\/a>C\u00e9ilidh Erickson<\/a>\u00a0is a Manhattan Prep instructor based on New York City.<\/strong>\u00a0When she tells people that her name is\u00a0pronounced \u201ckay-lee,\u201d she often gets puzzled looks.\u00a0C\u00e9ilidh is a graduate of Princeton University, where she majored in comparative literature. After graduation, tutoring was always the job that bought her the greatest joy and challenge, so she decided to make it her full-time job. Check out C\u00e9ilidh\u2019s upcoming GMAT courses<\/a>\u00a0(she scored a 760, so you\u2019re in great hands).<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"