Just answered this on another forum- will paste here:

I assume it's clear that neither statement is sufficient on its own. You could do the problem algebraically:

From (2) 12-m = r-12

From (1) |r| = 3|m|

Thus either r = 3m (if they are on the same side of zero) OR r = -3m (if they are on opposite sides of zero)

In each case, you'll get two equations/two unknowns- if you solve, in the first case you'll find m = 6, r = 18; in the second case you'll find m = -12, r = 36.

Or you could do the problem 'pictorially'. From 1), we don't know if m and r are on the same side of zero, or on opposite sides. Using 1)+2), we know that m and r cannot both be negative- but they could both be positive, or we could have that r > 0, m < 0. So we should get two different solutions, even using both statements. You can confirm that both cases are possible- you should be able to see that there will be one solution where m is negative and r is a positive number quite far to the right of 12, and another solution where both m and r are positive, and are closer together than in the first case.

No matter how you look at it, E.

_________________

GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com