Share your GMAT preparation tips or test experience

I have blogged about GMAT and MBA over the past three year and still counting. I will continue to do so but most of the questions I have received I have written about. So as not to sound like an old gramophone, please search for the topics on the right side bar and see if I have answered your questions. Thanks to Google Blogger stats, I can now see what were the frequently visited pages and keyword searches. I will continue to monitor and hope to address new areas.

One of the reasons I still blogged about GMAT is that I still believe that many GMAT takers and MBA aspirants want to overcome the fear of this test. I have done all I can to cover them. As our reader, I welcome you to share your GMAT preparation tips, how you did well and what insights you have for our readers about the GMAT test. Send me an email and I will be happy to post it. Let me know if you want to stay anonymous.

In fact, for those who have completed GMAT, you can do us a great service if you can lead a study group. I am now in Germany, and other core members are now overseas. We cannot guide you face-to-face; hence, whatever we can do via this blog or emails, we do our best. I hope to sustain this blog by having new people spending some of their time helping others. If you are like one of us, email me and let's help others.


Jimmy Low

No Calculator Please, We Are GMATers!

That's right. NO CALCULATOR on exam day. In fact, you can't bring anything into the exam room. All pens and plastic transparent sheets will be provided to you by the center.

So, it is time to crack some brain cells when you prepare for Quantitative section. The tricks in solving Quant(itative) questions are (1) to rephrase the question into an mathematical equation, (2) ask yourself what is the "x" they want you to solve, and (3) play the elimination game. Of the 5 answers, eliminate those that you know are wrong. This increases your chances of getting the right one especially when you run out of time.

Remember, you must answer all questions. Leaving any unanswered means heavy (and I do mean heavy) penalty on your final GMAT score!


Jimmy Low

Are You Prepared for GMAT?

Do you think you are ready for GMAT? One way to find out is to take the GMAT simulation test. Just like the real test you are going to sit, this computer-adaptive test will help you gauge your preparedness. If you do not "like" the score you got in this simulation test, then it is time to head back to your books and revise, or seek additional help.

Try the test now (test sets from GMAC, the official GMAT provider)
Or, Manhattan GMAT Prep's test.



Jimmy Low

8 FAQs on GMAT

Over the years, I have received questions on GMAT and have blogged about them. Here are some of the frequently asked questions that worth revisiting:

1. Where to take the test in Malaysia?
a. Central Region
Word Ware Distributors SDN BHD (next to Eastin Hotel)
Level 3, Unit 10, Block F Phileo Damansara
1Jalan 16/11, Off Jalan Damansara
Petaling Jaya, Selangor, 46350 Malaysia
Tel: 603-76652911 (speak to Willy)
GPS: 3 12 67 N, 101 64 34 E

b. Northern Region
Alpine Reliance (M) Sdn Bhd
1-3-16 Krystal Point Corporate Park,
Jln Tun Dr Awang
Bayan Lepas, 11900 Malaysia
Tel: 604-6422333

Register for the test here.

2. GMAT courses in Malaysia?
As far as I know, there are two - Princeton Preview in Wisma MPL (opposite the Weld Jalan Raja Chulan) and GMAT Zone in Taman Tun Dr Ismail (58B, 2nd Floor Jalan Burhanuddin Helmi)

You can contact them at: GMAT Zone KL or Princeton Review KL.

3. What about study group?
Occasionally, GMAT Malaysia might conduct study groups. Please write to me to enquire.

4. What books do you recommend?
Most of us used these books: Manhattan GMAT Prep books (8 books in total), GMAT Official Guide, Kaplan GMAT 800 and PowerScore Logical Reasoning Bible. There could be others but we found these books helpful, so far.

You can google and download verbal and quantitative questions. There are lots of them around to sharpen your skills.

5. Where to buy these books?
Go to Kinokuniya bookstore at KLCC. They have the best selection of GMAT books. The other bookstores barely stock the above books.

Alternatively, buy online from Amazon.com.

6. Can I do GMAT in 2 months?
In general, usually takes 6 months to 1 year depending on how discipline and committed you are. Don't be too ambitious. I rather you be realistic than to be disappointed, both with the whole process as well as the GMAT score that you want.

7. Any other advice?
Look for others who are planning to do GMAT. Study or discuss together helps. Since we receive lots of questions, we know who are those planning to take. We can pair you with them, subject to their consent.

Alternatively, join GMAT Club. You meet people from all over the world.

8. Any GMAT mobile apps?
Yes, we found two for iPhone and iPad. Check here (GMAT Club) and here (Manhattan GMAT). So far, none for Android or BlackBerry yet.




I wish you all the best. If you have any questions, feel free to email me.



Jimmy Low

It's The Approach That Counts

I like watching Nat Geo and Discovery channels on Astro. On one of the series about the US aircraft carrier, one of the fighter pilots talked about how he and his fellow pilots are trained to focus on the guide on the cockpit when they land on the carrier. They only have a small "window" of opportunity to land and if they missed that, they had to throttle to the max to fly away. They are not even supposed to worry about the guide cable which will hook at back of the plane and halt the plane when it lands correctly.

My study group members asked me how should they tackle GMAT questions. Well, the answer is and as I always reminded them (again and again) - it's the approach that counts.

Very often, the moment we see a question, we like to jump straight into working and only to find out that it took us more than 2 minutes and yet not getting the answer. When I practised, I took the above approach as show in the diagram.

Spend first 30 or so seconds to read, understand, rephrase the question, if necessary and formulate the approach. Remember, you only have this 30 seconds to think through and determine your best approach to solve in 4 or 6 steps.

The next 60 seconds is used for working. Start by eliminate not-possible answers. This improves your chances of striking the right one. By eliminating 2 not possible answers, you improve your odds from 1/5th to 1/3rd. If you can eliminate 3, then you increase it to 1/2th.

Don't forget that you need to click the answer in the computer. It takes time to move the mouse and click Next and Confirmed.

All this is done within 2 minutes window.

So, GMAT "pilots", start practising your approach.

Jimmy Low

Part 1: Tackling Quant Questions

Some members asked me what's "best" way to tackle GMAT quantitative questions. Well, I don't have the "best" answer but I have approached quant questions from different angles during my study and came out with one that suits me. You can give it a try and see if it suits you (always find an approach that you will be comfortable with).

In earlier blog, I wrote about "2-4-6" rule. I am sure someone might have invented this but let's say I gave it a name. Let's recap this rule: 2 minutes per quant question, 4 steps for "easy" question and 6 steps for "hard" question.

Now, we take this rule a few steps further. My approach to quant questions as follow:

1. When you read the stimulus and question stem, immediately take note of the topic(s) and sub-topic(s) you are being tested on. Yes, at times, especially "harder" questions, you are being tested on two or more topics or sub-topics. Therefore, your ability to syntisize the questions and pull them together helps a lot.

You might be asking what I do mean by "topic" or "sub-topic". GMAT Malaysia is using ManhattanGMAT Prep books as our guides; thus, you will find the structures in their books. As you study, you should build into yourself the principles and rules covered in each sub-topic.

2. Once you know what is being tested, immediately you should recall the principles and rules.

3. Now, apply those principles and rules to answer the question stem. Is it about Prime Factorisation? What do I need to know about prime numbers? What are prime numbers?

4. Most of time, the stimulus is in 2-3 sentences. Convert them into algebraic equation(s). This is what GMATters call "rephrasing".

5. Once you do this, you can see what the question is actually asking and at times, the answer just pops right in front of your face.

6. Look for the answer. At times, the answer is in another form e.g. in the form of inequalities. In this case, you think to know the rules of inequalities.

Okay, so much talk, show me the action. Here is one question from Official Guide (11th Edition):

PS Q26: If the quotient a/b is positive, which of the following must be true?

(A) a > 0
(B) b > 0
(C) ab > 0
(D) a-b > 0
(E) a+b > 0

This question is testing you on Positive/Negative Values and Divisibility but the answer choices are given in form of Inequalities.

When you rephrasing this question, value (a/b) being greater than 0. For a/b to be greater than 0, both a and b must be positive or negative. Either one cannot be negative, or the stimulus will not be true (in this case, the stimulus is a/b > 0).

Let's examine each answer choice.

(A) a > 0, but says nothing about b. Not determinable.
(B) b > 0, and like answer choice (A), says nothing about a. Not determinable.
(C) For a * b > 0, a and b must be positive or negative AND neither one can be negative. This is what we are looking for when we analyse the stimulus. Correct
(D) a - b > 0. If a is positive, then b must be smaller than a such that will still result in a - b as a positive number. Or, a can be negative and b can be negative such that the b is greater than a. Too many possibilities, not sure what values a and b could be. Not determinable.
(E) a + b > 0. If both a and b are positive, then this is correct. If a and b are negative, then this is incorrect. Or, either a or b is negative, then it dependable on which value is smaller negative value. Again, not determinable.

What I have done in analyzing and breaking down the stimulus is restating the stimulus into these two conditions:

i. For a/b to be greater than 0, both a and b must be positive or negative.
ii. Either one (a or b) cannot be negative, or the stimulus will not be true

And, answer choice (C) met these two conditions.

Get yourself into this regime and soon you will ace in both problem solving and data sufficiency questions.



Jimmy Low

"2-4-6" Rule for Quantitative

When we prepare for GMAT Quant(itative), most of us, if not all, will devise our own "rules" in answering maths questions. Then again, GMAT is pretty mechanical, so to speak. One rule that I find useful and which others will tell you the same is what I call a "2-4-6" rule.

So, what's "2-4-6"? 2 minutes for each Quant question (37 questions over 75 mins, ~2 mins per question), 4 steps for "easy" questions and 6 steps for "hard" questions. Now, what's "easy" and "hard" question? I can't say for sure because it is up to each individual. Some of us have weak spots in certain areas say, geometry but it would be a strong spot for others. "Easy" or "hard" becomes a relative measure. With sufficient practice, your "hard" questions can be "easy".

You must be asking how do I solve an "easy" or a "hard" question in 4 and 6 steps respectively. Well, you need to. 2 mins is not a "long" time. Before you know it, reading and thinking about the question alone will take you the first 30 seconds. Searching for the answer, clicking the radio button and press "Next" will take you the last 30 seconds. That leaves you with ~60 seconds to work out the answer. If you can't do a 4- or 6- step within that 60 seconds, then you know you started on a wrong footing - misinterpreted the question, applied the whole rule(s) or formula, or forgotten the basics.

So, to apply "2-4-6" Rule, it boils down to knowing your fundamentals. As simple as A-B-C.


Jimmy Low

JK's GMAT Debrief

I registered for the GMAT exam on 1st of October. I created my account on MBA.com, picked the center in PJ and selected a date. You can take the GMAT 6 days a week and there are options for morning appointments (between 8-9am) and afternoon appointments (1pm onwards). The GMAT is a 4 hour exam and you only have two 10 minute breaks in between so make sure you pick the time you think your brain works best. I picked a Monday morning because I was hoping for an empty test center and I know I will feel sleepy in the afternoon right after lunch. Besides, I get fidgety if I have too much time early in the day while waiting for an important exam to start. Once you've set up an appointment, it's time to whip out your credit card and pay for the US$250 exam. Any rescheduling 7 days before the exam will incur an additional US$50 while rescheduling within the 7 days will cost you an additional US$250 so pick wisely!

Now this is probably where I erred... while I started studying for the GMAT in June I did not maintain a disciplined regime. I will hit the books on some weekends, polishing up my rusty maths skills and doing the exercises. Only after I registered for the exam did I really start to study hard for the GMAT and boy did it hurt. This is not a glorified IQ exam. The GMAT is TOUGH! In hindsight, my advice is to take a timed GMAT CAT before you schedule (and pay) for the exam. Manhattan offers a free CAT and its the closest (with the exception of GMATPrep) to the real thing.

You've probably heard this before but I'll say this again. The OG is the BEST example of the type of questions that you will encounter on the GMAT. No other study guides come close to the OG in terms of question prose and difficulty. The other thing I found out is that attempting a timed GMAT exam is completely different from answering questions without the pressure of a timer. Use the GMATPrep software that comes with the MBA.com registration. Do not skip the AWA in your mock exams. Remember the GMAT is both a test of your intellectual capability, focus and stamina. Trust me, in the real test, you will be tired in the verbal section. I did 2 mock exams on the GMATPrep, one from Manhattan (it's free) and one from Kaplan. If you tried the Kaplan CAT exams, dont' worry about the skewed low scores. I reserved one GMATPrep CAT exam for the day before the exam. I got 650 and 690 on the GMATPrep tests. Not stellar but within the 80th percentile range.

Fast foward to test day. I arrived early at Phileo Damansara I, the test location, and parked in the basement. My advice is to park in Eastin because it cost me 11 bucks in Phileo. I think Eastin operates a 5 bucks per entry system. The test centre is quite pleasant and comfortable. Nice open spaces and bright red sofas. I passed my passport to them and they checked the details againts my record in PearsonVue's database. Your DOB and your name must match exactly. I was then asked to sign on an electronic pad (similar to those credit card machines), pose for a picture, and then place my index finger on the fingerprint reader. I was a little disappointed that the new palm vein recognition sensor was not utilised. It's a really cool technology that scans the distinct vein patterns in an individuals hand and it's faster than the fingerprint reader. (OK I'm a geek)

There were 2 other candidates who will take the GMAT with me (so much for the deserted Monday morning theory...). We were asked to read the terms and conditions and then we were required to place everything (keys, handphone and even coins!) in the locker. You will not be allowed to take anything into the test centre. The test administrator will then give you a laminated writing pad, a marker and some ear plugs. TEST THE MARKER as one of us had a dried up marker. The ear plugs are optional but I had to use it, which leads me to my next point. The test centre doubles up as a learning centre for a host of other courses. I was unlucky enough to have my test scheduled with an ongoing lecture. While the test rooms were quiet and separated from the rest of the office, it is right next to the lounge area and you will have people moving around outside the frosted glass doors.

The test room itself is really small and there are four cubicles. Each with a PC. Above the tables are three CCTV cameras so the entire test is recorded. Room temperature was pleasant. The test administrator will login and start up the GMAT CAT. Before the exam starts, you will go through the introduction cum tutorial screens similar to GMATPrep and you will then be asked to pick 5 schools to which your official GMAT scores will be sent. You do not need to know the institution's GMAT code as the school list is exhaustive. If you do not pick the schools on test day, you will be required to pay US$25 for the official scores to be sent to the MBA schools.

Now to the test itself.. the AWA went pretty ok. It's a good way to warm up before the Quant and Verbal section. I took the 10 minute break after the AWA to freshen up. In the quant section, I struggled a bit. I was hit with loads of DS and number theory problems (more than my prep tests). These were my weak points but I knew I had to soldier on and take the questions one at a time. I paced myself pretty well. The formula I used was to attempt 11-12 questions for Quant and about 13-15 questions every 25 minutes. It's better to break down the test to 3 sections than to limit yourself to 1.5-2 minutes per question. After the quant section, you are given another 10 minute break. Took the break, rested my eyes, freshened myself up again and got myself ready for the Verbal section. Remember to allocate some time for checking in and checking out of the test room. To check in and check out, the test administrator will need to take your finger print. It's pretty quick and painless but 10 minutes is really short so give yourself some allowance for the check in procedure.

The verbal section was quite tough. I was pretty confident about my CR and RC before sitting for the GMAT but the questions I got this time were really tricky and I had to guess for quite a number of the CR and RC questions. SC was pretty much similar to those you'd find in the GMATPrep and OG. By this stage of the test, I was pretty tired and it was difficult to focus on the questions. I will read the questions but I found that I needed to read it 3-4 times to digest it. Many times I had to verbalise the questions just to force myself to stay focus. I finally reached the last question with 2 minutes on the clock. I took as much time as possible and then clicked 'Next'. The ordeal was over :)

I filled up some questionnaires and finally the most important section, the score report. If you were expecting a 700 pointer GMAT debrief, this ain't it. I got a 630. I was quite disappointed frankly as I was hoping for something around 650. I've thought about retaking but upon reflecting, the schools I'm aiming for aren't the typical 700 pointer schools. The GMAT is important but it's not the only criteria. It's going to be a competitive year for business school admit but do not strike out a 'dream school' just because you tanked in the GMAT. Some elite schools have large GMAT spread but other elements of your admission package will need to be superb. Re-taking is another option but be realistic. Two 'low' GMAT exams will only reinforce the fact that the scores are not an anomaly. In the end its up to you.

Ok that's all from me.

JK

New Posting on Data Sufficiency

If you are looking for help on Data Sufficiency, read my updated posting - Data Sufficiency - Sufficient or Not?


Jimmy Low

A Learning Experience

It has been awhile since I blogged on GMAT. Since my last posting, I have received 5 enquiries about GMAT and how the beginners should start preparing for this "ultimate" test. 2 of these enquiries came from my colleagues. My company provides "internal" scholarship to potential leaders to further their education particularly on Master of Business Administration (MBA). I am one of these leaders intending to pursue my MBA next year (2009).

In my Jan 26 posting, I wrote about the resources that GMAT aspirants should have. The faster you get yourself started, the better. Don't waste time if you know what you want - your aim is MBA. GMAT is one of those "things" you must have to get you there.

GMAT Malaysia started by 5 young chaps. We got together one evening and spoke about how we can get together each Saturday and help each other out in our preparation. I am still making myself available every Saturday at our GMAT hangout in Starbucks HBSC Uptown to meet with anyone who interested to know more and study together.

I hold on strongly to this philosophy in whatever I do - "You learnt best when you make someone understand what you learnt" - be it at work, at my curricular activities, or at study. If the other person cannot understand what you are saying or teaching, it means you have not understand it yourself. I find this a powerful concept. I was a tutor during my final undergraduate year and my students came to me and thanked me for making accounting easier to understand. At work, I spent time explaining concepts - finance and technology - to my colleagues and bosses.

As a reward, my teaching strengthens my own learning. When I teach, I am reinforcing my own learning. The questions that my "students" asked help me think on "my feet" and some of my colleagues used to say "you can hear his brain working" *blushed*


Jimmy Low

Hit At Least 40 in Verbal and You Have A Home Run

Sometime back, I blogged about the importance of GMAT and the average GMAT score of the Top 50 USA business schools. Today, as I revisited my GMAT strategy, I discovered that the Verbal section is too important for anyone to miss; especially non-English native students.

(Source: Manhattan GMAT)

To score above 700, your Verbal score must be at least 40/60 and/or your Quant hitting 50/60 to pull your overall score up. No joke! What a pressure to do well.

Jimmy Low

Unravelling the Mystery of GMAT

Mention "GMAT" and many people will ask either "What is that?" or "Geez, that's one tough exam". Here is a video recording from Manhattan GMAT that I found useful in helping GMAT aspirants to understand more about this test especially in strategizing for this big test.

http://www.manhattangmat.com/virtual-online-gmat-recording.cfm
(Source: ManhattanGMAT)


Jimmy Low

Next GMAT Study Session - 8th March

For those who are interested to join the next study session, we will begin on 8th March at our usual venue - Starbucks HSBC Uptown at 2pm. See my first blog for the location map.

We are using Manhattan GMAT Prep booklets for our revision (We do not endorse any prep materials. If you wish to use other prep materials, by all means, go ahead.)

Week 1 (15 Mar) - Number Properties
Week 2 (22 Mar) - Fractions, Decimals & Percents
Week 3 (29 Mar) - Equations, Inequalities & VICs
Week 4 (5 Apr) - Word Translations
Week 5 (12 Apr) - Geometry
Week 6 (19 Apr) - Sentence Correction
Week 7 (26 Apr) - Critical Reasoning
Week 8 (3 May) - Reading Comprehension
Week 9 (10 May) - Analytical Written Assessment

For those who are using other prep books, please read up according to the above topic to synchronise with the rest of us. You will gain the most if you come prepared with your questions.


Jimmy Low

Now, Where Should I Start?

Well, as a first timer like myself, naturally you will want to know what GMAT is. Wiki explains it all. If you want something more official, then go to the "horse-mouth": The Graduate Management Admission Council.

One website that you should not miss is the MBA.com. This is your one-stop centre for anything related to MBA including registering for GMAT in your country.

What books do you need and where to get them in Malaysia? Let's start with the books.

a. The Official Guide for GMAT Review 11th Edition (or the latest) aka OG aka Orange book, in short.

This book is a MUST have. Hey, this book is from the creator of GMAT. How can you not have a copy of over 800+ past years questions? This is your GMAT bible. Make sure you pray to it each night. However, I find that the Math review - refresher on the mathematical concepts and English grammar rather "weak" (my personal opinion). The book did state that it is not mean to be a textbook. So, this means you need other books to supplement your studies.

GMAC also produces the Official Guide for GMAT Quantitative Review (green book) and the Official Guide for GMAT Verbal Review (purple book). For me, the Orange book is suffice.

b. What other supplementary books do you need? There are plenty in the market - Kaplan, Princeton Review, McGraw-Hill, Manhattan, Barron's to name a few. Go to the bookstore and check them out. Compare them and find out which will help you in your revision. Each of us has our own personal preference.

c. GMATPrep Test-Preparation software. This is a simulation of the real GMAT. Download the 26MB file from MBA.com.

Where to get these books? Head for Kinokuniya Bookstore at KLCC. They have a good selection of GMAT materials. The OG books (orange, purple and green) each costs about RM120-RM140. The other supplementary materials are about the same price too.

So, can you afford to buy many books? Maybe not. GMAT is a "costly" affair. Each test will cost you US$250 (or RM825 at exchange rate of RM3.30 to US$). Books and other herbal supplements will easily cost you another RM600-800.

d. Download a stopwatch at http://www.online-stopwatch.com/.

This is a timed exam. During your preparation, you want to pace yourself as you progress and adopt and adapt to the "right" speed of answering questions. Typically, many people will advise you to spend 2 minutes for each quant question and 1 3/4 minutes for each verbal question. I have tested this method and it did not work in my favour. In fact, it created more stress than necessary.

Medium and easy questions can be answered in less than 1 minute while tougher ones will take more. As I progressed, I found that I could complete a set of 31 quant questions within 30-50 mins out of an allocated 62 minutes, while a set of 31 verbal questions can be completed within 35-45 mins out of an allocated 57 mins. The no. of errors I made for each set of questions, on average, are less than 3. Thus, I have found my pace and the stopwatch helps me get into that rhythm. Bear in mind, you have a stopwatch during the real exam. Wall clock or watch does not help.

Now, that you know what you are getting into, be prepared.

Jimmy Low

Ready, Aim, Score .... Know Your GMAT Score Matrix

As I was learning more about GMAT strategy, I came across this website. Manhattan GMAT explains more about GMAT and its scoring system. If you know where you need to be strong in - quant(itative) or verbal, you can basically predict your GMAT score or focus more attention to.

(Source: Manhattan GMAT)

Let's see. To score at least 700, you need to hit 40 out of 60 on quant and 48 out of 60 on verbal. Each question is statistically weighted for its difficulty and being an adaptive test, you need to make you get more questions correct. While each test will be unique, for a 700 score (40 quant and 48 verbal), you should probably (best guess) get 33/37 correct for quant and 36/41 correct for verbal.

Again, while this gives you some leeways for guessing and making errors, you would probably want to put in extra efforts to score higher.


Jimmy Low

Data Sufficiency - Sufficient or Not? (Updated)

(Note: Since my last posting on this topic, I have learnt new techniques on answering Data Sufficient questions. Please reread this section for the new knowledge)

The Quantitative (Quant) section is divided into two sub-categories: Problem Solving (PS) and Data Sufficiency (DS). Out of 37 quant questions, about 13/14 questions or 1/3 will be on Data Sufficiency. For most of us, Problem Solving should be easy to score. However, I find DS more challenging:

1. We have been taught to solve problems, not on whether the information is sufficient to solve a problem; thus, the tendency to spend time and solve it.


2. We learnt by rote. We memorize workings and through practice, perfect our speed in answering problem solving questions.

Data Sufficiency tests us on the quantitative concepts and principles; the foundation. You are to decide whether the statements — either individually or in combination — provide enough information to answer the question.

(A) If statement 1 alone is sufficient to answer the question, but statement 2 alone is not sufficient.
(B) If statement 2 alone is sufficient to answer the question, but statement 1 alone is not sufficient.
(C) If both statements together are needed to answer the question, but neither statement alone is sufficient.
(D) If either statement by itself is sufficient to answer the question.
(E) If not enough facts are given to answer the question.

Here is a tip that I find helpful and is represented by these two triangle (below)

Now, which to use - AD/BCE or BD/ACE?

A and B refer to Statement (1) only and Statement (2) only respective. Depending on the question stem, which statement is easier to understand? Let's take this example.

Class A and class B took the same test. The average (arithmetic mean) score for class A was 79.5. What was the average score for all the students in both classes?
(1) The average score for class B was 80.5.
(2) Class B had 25 fewer students than class A.

For this question, you need these variables to solve the question:
a. average of Class A (given)
b. average of Class B
c. no. of students of Class A and B or ratio of Class A and B.

Statement (1) only average of Class B is given. Not Sufficient; eliminate A and D.
Statement (2) only does not tell us how many students in Class A and what's the average of Class B. Not Sufficient; eliminate B.
Both Statement (1) and (2) also not sufficient because the missing part is still no. of students in Class A or the ratio of Class A and B students. Eliminate C.

The correct answer is "E" and I took less than 1 minute. By rephrasing the question stem and knowing what information you need, you can play the elimination game. I started with Statement (1); which alone is will not solve the question, thus, immediately eliminate answer A and D. You have increased your chances of finding the right answer from 20% (1 out of 5) to 33% (1 out of 3).

You can also tackle this question starting with Statement (2) as folllows:

Statement (2) does not tell us how many students in Class A and we do not know what is the average of Class B. Not Sufficient; eliminate B and D.
Statement (1) alone does not tell us about no. of students of Class A and B or their ratio. Eliminate A.
Both Statement (1) and (2) also not sufficient because the missing part is still no. of students in Class A or the ratio of Class A and B students. Eliminate C.

Whether you use AD/BCE or BD/ACE, you can still come to the right answer. Then does it matter which one? Well, whichever statement (1) or (2) is "easier" for you to start. If Statement (1) is "easier", then use AD/BCE, use BD/ACE. After some practice, you should be able to master this technique and shave 1 minute from "easy" data sufficiency questions. If half of data sufficiency questions, say 6 questions, are "easy" ones, you have saved 6 minutes which you could use to tackle 2-3 "difficult" questions.

Look at the triangle again and visualize how it works. After a few attempts, you should be able to master this triangle. Draw this triangle at the start of your test and use it whenever you come across DS questions.

Jimmy Low

P/S: As you noticed, I use the quote/unquote marks when I mentioned "easy/easier" and "difficult" questions. What is "easy" for me might be "difficult" for you. It is a question of relative difficulty. But, with a strong foundation and more practice, you can handle them.