The "math" behind this question is such that there are several different numbers that "fit" the given "restrictions"; in that way, we can use a bit of "brute force" to quickly come up with the answer.
We're told that a two-digit positive integer will differ from its "reverse" by 27.
I'm going to 'play' with this math a bit.....
IF we use....
12 and 21 then the difference is 21-12 = 9 This is NOT a match
13 and 31 then the difference is 31-13 = 18 This is NOT a match. Notice how the difference increases by 9 though!!!!!
14 and 41 then the difference is 41-14 = 27 This IS a match.
The question asks for the difference in the two digits involved. Using these values, the answer is 4-1 = 3
I mentioned at the beginning that there were several numbers that "fit" what this question was asking for. They are 14 and 41, 25 and 52, 36 and 63, 47 and 74, 58 and 85, 69 and 96.
GMAT assassins aren't born, they're made,
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