Still having a tough time with DS...

For some reason, trying to work with statement 2 first really works.

Not always of course. And there's no REAL reason. For me, I think it was just that I'd examine statement 1, determine it was insufficient, and then move onto statement 2 but forget to check it alone, without statement 1. So I was answering C an awful lot when the answer was really B. For some reason, doing it backwards let me catch that error a lot more often.

Makes sense. I wonder if there is a statistic out there (somewhere) that has the ratio of A:B:C answers in the OG DS section.

Hey Valleyball,
Here are a few techniques I've come up w/ for DS:

1. Try to rephrase in the context of the given statements 1) and 2). This means simplify the question which makes it easy to plug in the information given by the statements (This may be nothing new).

2. When plugging in required, make sure to test out -, +, even, odd, fraction, x>0, x<0, 0 etc. when needed. All of these will not need to be tested so use some logic to decide which are needed for the particular problem.

3. Realize that statement 2 often only adds a small, but necessary, bit of information which compliments statement 1 (or vice versa). For example, a quadratic function may yield -2,2 for 1) and 4,2 for 2). Together, you know its 2. (You have probably encountered all this, but i think its important to note that such problems occur quite frequently).

4. The DS diagrams are often drawn to confuse you, so use the info given and make ur own diagram.

5. On DS word problems, try to figure out what variables could give you what is asked for. If 1) and 2) are insufficient alone, treat them as one big word problem. Remember - whatever the number of variables in the problem, you will need the same number of equations relating at least one of the variables. It helps to translate the stem into algebra, look at the number of variables, and see if you can manipulate the equation to give you what the question is asking for. (For example, to find x-y, you need not necessarily know the values of x and y; maybe you can put them on side of the equation).

These may seem obvious but they give a good idea of how the test makers think, and in what ways they set up traps.

Hope it helps!!

Another frequent trap is when statements 1 and 2 give you identical information but stated differently.

This is particularly common for problems that have two unknowns, and you're given two equations, so one would assume that together they would be sufficient. But then, both equations end up being multiples of one another, for example.

You don't need to solve all the way but you should do a few steps of work just to make sure that the info you THINK you have really exists.

yb - I think I can use #5 immediately. I always get confused combining the two statements.

coffee - in your example, the answer would be D, not C, right? I always get this one wrong.

Thanks for the great advice! After my study session last night, I was feeling kind of low so I had to turn to The Club for some help and motivation.

I appreciate it.

Any other ideas?

In my example the answer would be either D or E.

If either statement alone is sufficient then it would be D.

If each statement is insufficient, given the equivalency of the two statements, the answer would be E.

Gotcha - I should have said D or E, but that's what I meant. Did you take the GMAT already?

By the way, I thought the last 50 or so DS in OG11 were good practice... (they are relatively tougher though, I got several wrong)

Man, you can probably teach a prep course!

Congrats...

Thanks. But nah. Being able to DO isn't the same as being able to TEACH - a mistake lots of people make when finding a tutor and assuming they'll be good just cause they scored highly. I can often intuitively understand the answer but I'm not great at explaining how I arrived at it.

Anyway, best of luck to you!

My approach is similar to yb's:

1. Rephase the question into a math statement/equation/diagram. In the process, simplify/factorize/expand/etc as and when necessary - especially for "difficult" questions.

2. Circle the variables that are needed to solve the equation. This will help you to see:
a. how many variables are needed to solve the equation, and
b. which variables are needed

The idea is to focus on the variables that are needed to solve the problems, and not on solving the problems themselves.

3. Then go thru the statements A & B to see if they provide the values of the circled variable(s). Most of the time, you will need to rephase the statements as well.

Hmm, I never heard about the circle thing. I'm going to try it out tonight. Thanks tkkoh!

This Club is probably the greatest and coolest one around!
All you guys are really great! One guy posts his/her concern and there are so many suggestions/advices!!
Three cheers to GMAT Club and all the wonderful folks!!

I second that. At first I was a bit skeptical about an "online club" but the intelligence of the members and most importantly, their willingness to help one another has been a pleasant surprise. A big thank you to everyone for contributing!

Great post! Keep up the good work and keep the spirit of gmatclub alive. I have been through what you guys are going through now and can certainly ascertain that gmatclub is what it is only because of its members.