Search found 18 matches
32 terms, 31 of which are a bit less than 1/33. So adding them together yields a bit less than 32/33, which is close to 1. So (E).
BTW: 31 out of 32 terms are a bit more than 1/64. So adding them together yields a bit more than 32/64, which is 1/2.
- by Testtrainer
Tue Jan 26, 2016 10:52 pm- Forum: Problem Solving
- Topic: (1/33)+(1/34)+……+(1/63)+(1/64) is including in which of
- Replies: 3
- Views: 1352
Pick m = 4, n = 2.
Sum of 2 + 3 + 4 = 9
(A) 9
(B) 7
(C) 5
(D) 3
(E) 9/2
Variables in the answers: always think about picking numbers, staying away from zero and one, and you should be good to go.
- by Testtrainer
Tue Jan 26, 2016 10:46 pm- Forum: Problem Solving
- Topic: If the sum of the first k positive integers is equal to, k(k
- Replies: 2
- Views: 1439
- by Testtrainer
Tue Jan 26, 2016 10:16 pm- Forum: Problem Solving
- Topic: Change in Ratio - Boarders:Day Scholars
- Replies: 4
- Views: 1416
Huge fan of your comments about those questions are not actual GMAT style, but I believe that "Fair Use" enables folks to post actual OG questions (citations would be good). As long as its less than 10% of the material and neither party profits, then this stuff can be used. You guys over a...
- by Testtrainer
Thu Apr 02, 2015 10:24 am- Forum: Problem Solving
- Topic: calculation problem
- Replies: 5
- Views: 1953
This question is indeed too advanced for the GMAT. It actually tests an abstract concept in Probability sometimes known as the Monty Hall problem (from Lets Make a Deal). It goes like this: You're on Lets Make a Deal and are asked to choose one out of three curtains, one which has a car behind it, t...
- by Testtrainer
Thu Apr 02, 2015 10:12 am- Forum: Problem Solving
- Topic: Trick Question?
- Replies: 9
- Views: 2953
Video explanations for 6 high-level OG diagnostic questions
A very nice Beatthegmat staffer told me that I could post here. I have put together some video explanations to 6 high-level Problem Solving questions from the OG diagnostic. These free videos are part of my free preview for my upcoming online GMAT math course, which will be released in the Fall of 2...
- by Testtrainer
Sun Apr 01, 2012 10:15 am- Forum: Problem Solving
- Topic: Video explanations for 6 high-level OG diagnostic questions
- Replies: 0
- Views: 680
Marta bought several pencils. If each pencil was either 23 cents or 21 cent, how many 23 cents pencil did Marta buy? 1) Marta bought a total of 6 pencils 2) The total value of pencil Marta bought was 130 cents. I think the key to answering this very difficult question is to know two things: 1) Penc...
- by Testtrainer
Tue Nov 29, 2011 10:20 am- Forum: Data Sufficiency
- Topic: is linear eqn with 2 variables sufficient
- Replies: 16
- Views: 2280
What is the best teaching approach (pedagogy) to the GMAT?
I am actually a GMAT trainer and am having a debate with a soon-to-be online educational company as to the most effective teaching approach (pedagogy) to the GMAT (or any standardized aptitude test, for that matter). I believe that a rigorous, systematic, step-by-step method that, by definition, lim...
- by Testtrainer
Mon May 02, 2011 4:36 pm- Forum: GMAT Strategy
- Topic: What is the best teaching approach (pedagogy) to the GMAT?
- Replies: 0
- Views: 1208
Step-by-step method for dealing with remainder questions when picking numbers or plugging in answers doesn't apply: 1) Rephrase as equation: remainder = decimal x divisor R = .45b 2) Rephrase decimal using 10^-x R = 45 x 10^-2b 3) Prime factor all terms R = 3^2 x 5 x 2^-2 x 5^-2 x b 4) Combine term...
- by Testtrainer
Sun Mar 06, 2011 6:44 pm- Forum: Problem Solving
- Topic: Number Properties - Advanced
- Replies: 10
- Views: 3265
I solved this nasty question by using a formula and knowing what the GMAT likes to test. I confess that I was making a darn good guess because no way could I have done in the math in less than 5 minutes. Beyond the whole Venn-diagram/formula/grid concepts, the GMAT also likes to test the following b...
- by Testtrainer
Sun Dec 12, 2010 9:54 pm- Forum: Problem Solving
- Topic: 800score.com overlapping set problem
- Replies: 28
- Views: 6031
Remainder questions can be a real pain. Most test-takers should either plug in answers or pick numbers. In this particular case, plugging in answer choices (which I didn't see) would probably be a snap. When possible, picking numbers is also quite easy (I believe an example can be found in the OG qu...
- by Testtrainer
Tue Aug 03, 2010 5:21 pm- Forum: Problem Solving
- Topic: Need help with remainder problem
- Replies: 3
- Views: 1648
So I think I might have answered my own question, but I could use some confirmation. The following equations: 3x = 2y, 5y = 3z, and 5x = 2z are indeed 3 distinct linear equations with 3 unknowns. However, each linear equation has a y-intercept of 0, meaning that all 3 equations intersect through (0,...
- by Testtrainer
Sat Jul 10, 2010 9:59 pm- Forum: Data Sufficiency
- Topic: DS "distinct linear equations rule" - exception?
- Replies: 8
- Views: 5150
So sorry, but not quite. Here's the deal: whenever I see multiple equations with multiple variables, I run through various "checks": are they linear? are they distinct? is there another way to solve? Typically, I can see quite quickly whether the equations are distinct. In this particular ...
- by Testtrainer
Fri Jul 09, 2010 9:51 pm- Forum: Data Sufficiency
- Topic: DS "distinct linear equations rule" - exception?
- Replies: 8
- Views: 5150
Thanks for the super-quick reply. I did indeed see what you worked out. I guess my question is: how can I learn to recognize that such seemingly distinct equations are actually not? Otherwise, I might be tempted to work out every single DS equation I come across (which I know I shouldn't do), just i...
- by Testtrainer
Fri Jul 09, 2010 9:26 pm- Forum: Data Sufficiency
- Topic: DS "distinct linear equations rule" - exception?
- Replies: 8
- Views: 5150
DS "distinct linear equations rule" - exception?
What is the value of x?
(1) 3x = 2y
(2) 5y = 3z and 5x = 2z
The answer is E! I checked the math, and its true - you can't solve for any variable. However, aren't these equations distinct and linear? What rule of math says that I can't solve? Thanks for any help.
- by Testtrainer
Fri Jul 09, 2010 8:53 pm- Forum: Data Sufficiency
- Topic: DS "distinct linear equations rule" - exception?
- Replies: 8
- Views: 5150