Data Sufficiency

Just to find a fraction a/b here that works with Statement 2, you need to expand 1/7 to five decimal places, which is not the kind of thing you'd ever need to do on a real GMAT question. So this isn't a realistic problem, and I wouldn't worry about it.

And one small correction:

DavidG@VeritasPrep wrote:
a/b could be 1/7, which is .14386, rounded to the near tenth = .1

1/7 is equal to 0.142857...

Matt@VeritasPrep wrote:
Well, I dunno. Sevenths have interesting cyclic properties (1/7 = .142857..., 2/7 = .285714..., 3/7 = .428571..., etc.) and if I were a testwriter I'd consider using them. Just because there aren't OG questions testing this doesn't mean there *couldn't* be.

I do not base my opinions about the scope of the GMAT solely on what is found in the OG, and I do not understand why you'd make that insinuation.

I do base those opinions on the 5,000-10,000 official Quant questions I've seen. I've seen exactly two real questions where a test taker might contemplate using long division to produce a repeating decimal. In both you could avoid long division if you knew the decimal expansion of 1/9, and in both, the decimal repeated after three digits. When I say the GMAT does not test whether you can expand a repeating decimal to five places, or whether you know the decimal expansion of 1/7 to five places, I'm basing that on looking at every published official question I've been able to find from the last fifteen years. If you have evidence to the contrary, I'd be interested in seeing it.

Nor, incidentally, do I think they could test such things, even if they haven't in the past, but I'd have to get into a long technical discussion to justify that. But in short, GMAT question writers cannot simply test whatever mathematical properties they find interesting. Questions need to meet the assumptions of Item Response Theory, and need to differentiate clearly among test takers at different ability levels. I have good reasons to think questions about long division would not do that.

And yes, the GMAT does test cyclic properties, but it does so in other ways - in word problems with repeating patterns of coloured tiles, in units digits questions with exponents, in sequence questions where the sequence loops.