paul2432

I agree wtih kamakshi. For me at least it is easier to solve these this way: Start wtih 100 people 50 take yoga. Of these 28% or 14 have heart attacks. 50 take the medicine. Of these 30% or 15 have heart attacks. Hence probability that a person that has a heart attack took yogo is is 14/29. DWarrior: If you apply your solution to the medicine you get 0.375. (0.5*0.3/0.4). Clearly since everyone takes yogo or the medicine the two should add to one. That they don't shows your solution is incorrect. The problem with your method is that P(heart attack) is not 0.4. That is the probability assuming no treatment, but everyone does one of the treatments. The probability of a heart attack is a weighted average of the probability after the two treatments. P(heart attack) = 0.5x0.28 + 0.5x0.3 = 0.29 If you use P(HA) = 0.29 you get the same answer as Kamakshi. Paul

1) Yes 2) No 3) Yes Re (3) you can't bring anything into the exam area, so it will do no good to bring the codes with you.

Q1: If n is a multiple of d then n=ad. The multiples of d Q2: I get Seven. The fourth Tuesday of the month could be any of the 22nd through the 28th depending on when the first Tuesday of the month falls. Q3: The number of rubies must be divisible by both 6 and 8 for the ratios to be possible. Hence the smallest number of rubies possible is 24. If there are 24 rubies, then there are 20 diamonds and 9 emeralds for a total of 53. Paul

Here is another way. Compare both to 100021 x 90021 A is 189 x 90021 more B is 189 x 100021 more B is clearly bigger. Paul

As n gets large (100 is large), then a binomial distribution is approximately a normal distribution with mean np and standard deviation [np(1-p)]1/2 In this case the mean is 100 x 0.5 = 50, and the SD is [(100)(0.5)(1-0.5)]1/2 = 5 Hence 60 is two SDs above the mean. The probability of two SDs above the mean or more is about 2.5%. Binomial distribution - Wikipedia, the free encyclopedia That said, I don't think the GRE asks questions that require knowing approximations of the binomial distribution. If it did ask this question the answer choices would be so that the answer would be fairly obvious with a little thought (e.g. all answers but one above 50%). Paul

I've never seen ETS present the x-y axes without an "O" at the origin. The GRE Practice book gives some guidance on what can be assumed in figures (see page 9). http://ets.org/s/gre/pdf/gre_practice_book.pdf I strongly recommend reading through this as well as the GRE Math Guide. Paul

Download Powerprep from the GRE website and do all the practice problems and sample tests. The problems there are the most realistic you will find. It sounds to me like you are favoring brute force solutions to problems where an elegant solution may be possible. If you "see" the fast way to do a problem you can often solve it in seconds where it might otherwise take several minutes. This is particularly true of the quantitative comparison problems where an exact solution is often not necessary (or even possible). The bad news is that this type of intuition is not something that can easily be developed overnight. On the other hand, you may just lack the confidence to select an answer without fully vetting its correctness. Good luck on your exam. Paul

Q1: (A). They hypotenuse of a right triangle is always longer than either of the legs. The other information is irrelavent. Q2: Agree with (B) Q3: (B). A must be 2 or 3. If it was 1, then D would also be 1 violating the condition that the letters represent different numbers. If A is 4 or more than the product would be a 4 digit number. B must then be less than 5. If it were more than 5, then the thousands digit of the product would not be the same as the units digit. Q5: © I assume this refers to the graph with the 50 degree angles. The third angle of the small right most triangle is 80 degrees (three angles on a line add up to 180). Thus x+80+50=180 (three angles of a triangle add up to 180). Therefoer x=50. Q6: Question doesn't make sense. Paul

(A) Something/someone X may Y. B, C and E are clearly opposite in tone and so can immediately be eliminated. D does not quite fit. It is more like someone illustrious may be lauded rather than laud someone else. Paul

I'm in.

The answer is 8C3. Integers less than 10,000 : GMAT Problem Solving (PS) Paul

I can think of two reasons: 1) Canada has fewer universities 2) Canada has colder winters which may not appeal to some I have no idea if these are the actual reasons. Paul

ETS 10th was helpful. It is mostly problems without explanations which worked for me. When I did make a mistake I was always able to figure it out. In fact, not having the explanation handed to me was probably beneficial. I've found a lot of the other material was occasionally useful (Barron's, Kaplan), but often contained questions that I felt were flawed. For example, some of the Data Interpretation questions, the graphs were too small and the answer choices to close together to be able to choose the correct answer. (for example, the tick marks might be in increments of 25, but the answer choices might be only 5 apart). ETS problems never had this issue. Paul

Small correction. A number is divisible by 8 if its last three digits are divisible by 8, not if the sum of the last three digits are divisible by 8. Paul

Do what works best for you. I read the passage in detail, and then answer the questions. That may or may not work best for you. I don't recommend answering questions without having read the entire passage, and read in detail at least the part that pertains to the question. Whether you read the question before the passage is up to you. Paul

Background I finally took my GRE this past Saturday with scores of 800Q and 770V (still waiting on AWA). It all started in the spring of 2009 when I was finishing a part time MBA program. I had returned to school for the MBA fifteen years after completing my undergraduate degree. I really enjoyed the MBA and decided I wanted more education (my company has a fairly generous tuition reimbursement program). I started studying for the GRE. For various reasons, I put my studying on hold, and then resumed studying in earnest around June 2010. Study Plan The main study materials I used were ETS Big Book, ETS 10th Edition, Powerprep, Barron’s GRE, Barron’s 800 Essential GRE Words, and Kaplan GRE. I also visited these forums regularly. I’ve always been good at math, and at first almost took for granted that I would get an 800 on the quantitative section. However, I soon realized that while I could solve every problem, I invariably made some kind of silly mistake on the practice exams. I decided I would do as many practice problems as I could with the intent of increasing both speed and accuracy. I would use the time gained from faster problem solving to check my work (more on this later). Along the way, I brought to the forefront of my mind many simple rules of geometry and algebra that I already knew or would have been able to derive. However, having these ideas fresh in my mind greatly increased my speed. I cannot stress enough the importance of practicing the quantitative section even if you are very good at math. It is so easy to make a silly mistake and cost yourself a perfect score. I started studying the verbal section like most people, by memorizing lots of words. I found that I already knew most of the words (maybe 85%) on the Barron’s list and that many of the words I did not know were not showing up on practice tests (also a lot of words on practice tests I did not know were not on the Barron’s list, even some of Barron’s practice questions had words not on their list). I decided instead to focus on practice problems rather than word memorization. If I came across a word in a practice problem that I did not know, I would memorize it. It took some practice, but reasonably quickly I developed a pretty good feel for the reading comprehension and sentence completion questions. I also got pretty good at using the process of elimination. Fairly often, particularly on an analogy question, even if I was unsure of a word, I was able to use the process of elimination to come up with the correct answer. The test prep books provide suggestions on how to eliminate answer choices when you don’t know the meaning of all the words, so I won’t repeat that here. Going into the exam, my CAT scores were 800Q, 790V on Powerprep 1 and 790Q, 730V on Powerprep2. I also took three Kaplan CATs with scores around 780-790Q and 650-780V. My goal from the exam was 800Q, 750+V. Test Day I was scheduled to start the test at 8:00 AM and arrived at the test center at about 7:30 AM. I provided my ID and completed the necessary paperwork. ETS requires writing in cursive (not printing) a confidentiality statement. I haven’t written in cursive in decades so this was a little awkward. I brought a sweatshirt with me, but the test center indicated I would need to wear it throughout the exam (taking it off was prohibited) so I elected to put it in the provided locker. Once in the exam room I went through some preliminary screens and was then presented my issue topic. The test center provided hearing protection which I immediately decided to use. The ear muffs were a little uncomfortable, but I found the noises of other testers too distracting. If I was going to test again, I would bring foam ear plugs. The issue topic was uneventful. I think I did a reasonable job. One thing that helped was I recalled a recent editorial I had read in the New York Times that gave me some ideas for the essay. Next I received the argument topic. I think I covered this reasonably well, but I was slightly less pleased with this essay (probably because I was not able to refine it as much, given only 30 minutes for the argument compared to 45 minutes for the issue). After the argument essay, I decided to take the ten minute break. I had brought a banana, so I went to my locker and ate it at that time. The next section was the verbal section. Obviously, due to the confidentiality pledge, I cannot go into any details. I did come across one word I had never seen before. Overall I had three reading comprehension passages (two short, one long). The first came at question nine. I found the third reading comprehension passage to be particularly confusing. Unfortunately, I had spent a little too much time on some of the earlier questions and had to rush through it. I next received the quantitative section. If you are used to big book or ETS 10th format, the quantitative section may be a little startling in how much it jumps around in question types(same really for the verbal section). I proceeded very carefully, checking my answers whenever possible. I was glad I did this, because at least three times I changed my answer after I had made my selection but before hitting the confirm button. Each time I had made a silly error or misread the question (for example on a data interpretation question I misread the vertical scale on a graph). This approach left me a little time crunched for the last four questions. One of the questions, I solved algebraically but for some reason the answer did not seem right. After going back and forth quite a bit, I settled on my algebraic answer (which I thought about after the exam and believe was correct, I don’t know why I got so bogged down). That left me even more time crunched for the last two questions. I made an educated guess on the second to last question (which I later confirmed was correct), and the last question was easy enough to solve with the 45 seconds I had left. Next I was asked to complete a voluntary experimental section with a possible $250 prize. I decided to try it. This section was a verbal section with some interesting question types. It was much easier than the actual exam, and I think I got them all right. At this time I was a little concerned about my score. I knew I had done well enough to get into the schools of my choice, but wasn’t sure if I had met my goal scores. I decided I would view my scores. I did, and was pleased with the result. I next selected the schools to receive my scores and then the exam was over. I signed out of the exam room at 11:14 AM.

According to ETS large score improvements are rare. That said, practice, practice, practice. Also don't just memorize words, practice the verbal questions. There is a lot more to the verbal section than vocabulary. Also, analyze your mistakes and focus your practice. Paul

Another solution: x + y = 43 x2 - y2 = (x+y)(x-y) = 43(x-y) = 43 --> x-y = 1 Add the two equations together to get: 2x = 44 --> x=22 --> y=21. Paul

The key is the second sentence of the second paragraph: Recent studies suggest another way in which species compensate for the inefficiency of wind pollination The first paragraph is mainly background. The passage switches direction to its main point in the second paragraph. (A) is wrong for two reasons. First the question of evolutionary adaptation is not mentioned until the fourth paragraph, so is not likely the main point. Second, the passage talks about evolutionary adaptation, but says nothing about a debate about evolutionary adaptation. In fact, it presents the current understanding (that adaptation is an open question) as if it is widely agreed upon. If (A) was the correct answer you would expect to see statements regarding the positions of various scholars and how they defended them. In summary, a passage about a subject is not the same thing as a passage about the discussion of a subject. Paul

The answer is wrong. You are correct about 4x4x4. Let the Maryland players be 1,2,3,4 Let the Vermont players be 5,6,7,8 Let the Emory players be 9,10,11,12 Then the possible teams are: 1,2,3 | 5,6,7 | 9,10,11 1,2,3 | 5,6,7 | 9,10,12 1,2,3 | 5,6,7 | 9,11,12 1,2,3 | 5,6,7 | 10,11,12 1,2,3 | 5,6,8 | 9,10,11 1,2,3 | 5,6,8 | 9,10,12 1,2,3 | 5,6,8 | 9,11,12 1,2,3 | 5,6,8 | 10,11,12 1,2,3 | 5,7,8 | 9,10,11 1,2,3 | 5,7,8 | 9,10,12 1,2,3 | 5,7,8 | 9,11,12 1,2,3 | 5,7,8 | 10,11,12 1,2,3 | 6,7,8 | 9,10,11 1,2,3 | 6,7,8 | 9,10,12 1,2,3 | 6,7,8 | 9,11,12 1,2,3 | 6,7,8 | 10,11,12 I'm not going to type it all out, but the above can be repeated three more times be substituting 1,2,3 with (1,2,4), (1,3,4) and (2,3,4) for a total of 64 possible teams. Paul

The problem doesn't make clear if the balls are the same or different. For example, if the balls are A, B, C, D, E is: Tin 1: A B C D Tin 2: E a distinct way from, Tin 1: B C D E Tin 2: A ? The answer is 45 if we count both ways, but 56 if we count just one of these. Paul

Q1: C Number of line segements is 5C2, number of triangles is 5C3. Both are equal to 10. Note the stipulation about no three points falling on a line is necessary, because if three points did fall on a line, they would not form a triangle. Q2: Agree with your answer. Q3: C (-1 + 3x)2 will always be greater than or equal to zero. The minimum occurs when it equals zero (x=1/3). In that case (-1 + 3x)2 + 4 = 4 Q4: What are the answer choices? Q5: Does "just above 50" mean n=51? Is just one ball chosen? If n is even p=50% If n is odd p=(n-1)/2n Q6: 27 The maximum distance is twice the radius plus the distance between the centers. Q7: A (a/b)/c = a/(bc) = (1/c)(a/b) a/(b/c) = (ac)/b = ©(a/b) Because ab>0, a/b is also greater than 0. Thus dividing both expressions by (a/b) does not change the relationship. The comparison becomes: A: 1/c B: c Because 0 1, there for A>B. Paul

Yeah, I got it backwards (confused in with out). Paul

e cannot equal 496 or 504 because it is given in the problem that e Paul

It does not follow from S/T > 1/3 that T/S > 3. Multiply both sides by 3T/S to get 3(T/S)(S/T) > 3(1/3)(T/S) --> 3 > T/S --> T/S Paul