I can't recall the exact question I had. However, I remember that there was one arithmetic progression question. The question was to find the sum of the first x terms. The sequence was alternating, i.e. +ve number followed by a -ve number and so made the question relatively easy. Hope this helps.

ur kidding

im so scared now

i didnt know sequences like that were on the gmat

god help me

[b]*** The Question listed here is not a question that I saw on the actual GMAT ****
[/b]

Sorry if I scared you by the description of the question I didn't mean to. The question wasn't all that difficult. Here is what the question looked like.

The series was something like this: a1 = 2, a2 = -1, and for n>2 an = a(n-2) as in the (n-2)th term of the series. i.e a1=a3=a5=a7=a9=2 and a2=a4=a6=a8=10=-1 Find the sum of a1+a2+a3+...+a10

Obviously the sum here is 5. The question is really simple, and you didn't really need to know much about the theory behind arithmetic progressions. I think geometric progression is out of the question as it's much too complicated to be tested on the GMAT.

I also think it is rare.

It is difficult subject.

i am going to give my gmat in about 2 months from now. I am preparing for this area of quantitative section. It is a difficult topic but once you understand , its easy. The best help would be to go through the formulas before the test day instead of worrying about it for 2 months..