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Re: Two positive integers a and b are divisible by 5, which is their [#permalink]
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09 Jan 2017, 06:54
Hi All,
basically this question does not require complicated math at all, even though I solved it using the math too. But after some considerations I came up with this approach:
The questions asks us for the concrete values of a and b. As long as the solution is not a=b (which is explicitely denied in statement 2 and GMAT statements never contradict each other) we can either find at least 2 values or the information is not sufficient at all. As neither in statement 1 nor in statement 2 nor in the question stem itself is given any clue, which of the value has to be assigned to a and which to b, the answer choice will always be E.
The situation would change, if e.g. statement 2 were "The smaller number a ..." and you would have to do the math to come up with C instead of E.
But the question is, is it worthwhile to watch out for such a 'simple' solution or not (i.e. hurl oneself immediately into the math). I guess such 'simple' cases are quite rare and it definitely costs time to check for such cases. It will certainly cost you ~ 10 secs to check for the above situation and for a positive will shortcut the answer so that you save 100 secs (it took me 180 seconds to solve this one), so with 15 DS questions, it will cost you ~ 150 secs for the check and, as there is probably only one 'simple' case, will save you ~ 100 secs, the bargain is negative.
What is your opinion or your experience? Are there other 'simple' cases that might make it worthwhile to watch out for them in a bunch? Is there some statistics available to confirm either way  check first or hurl into math immediately?
