Applied Problems

[datonman]

If a two-digit positive integer has its digits reversed, the resulting integer differs from the original by 27. By how much do the two digits differ?

A) 3
B) 4
C) 5
D) 6
E) 7

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Hi datonman,

You can actually TEST Values on this question - you just might need to experiment a little bit to find a pair of numbers that fit the given information (there are several though).

Let's try 12 and 21....the difference is 9
How about 13 and 31....the difference is 18

Notice that we're dealing with multiples of 9.....

How about 14 and 41...the difference is 27. This is an exact MATCH for what we're looking for. The difference in the digits is 3.

You could also have used....
25 and 52
36 and 63
47 and 74
58 and 85
69 and 96

Each of these possibilities fits the "rule" that the difference is 27 AND provides the exact same correct answer: 3

Final Answer: A

GMAT assassins aren't born, they're made,
Rich

[DavidG@VeritasPrep]

If a two-digit positive integer has its digits reversed, the resulting integer differs from the original by 27. By how much do the two digits differ?

A) 3
B) 4
C) 5
D) 6
E) 7

If we call 'x' the tens digit and 'y' the units digit, the original number can be depicted as 10x + y. If we were to swap the units and the tens digit, the number would be 10y + x. If we know that the difference between the two is 27, we'll get:

(10x + y) - (10y + x) = 27
9x - 9y = 27
x - y = 3

So the answer is A