Gmatprep550 wrote:
Is t =|r - s|?
(1) 3r > 3s
(2) t = r -s
(1) Nothing about t NS
(2) t = r-s. It is tempting to mark sufficient, but lets test some values Let r=-2 t=-3 then t =-2--3 =1 and |r-s| - |1| =1 Yes
let r=-2, s=1 then t =-2 - 1 =-3 and |r-s| =|-3| = 3 NS
(1) and (2) 3r>3s --> r>s And t=r-s Logic tells us that t will always be positive thus suff, however we can test some values just to be sure.
Notice for values of r and s r >S So, let r=-3, s=-4 then r-s = -3 --4 = 1 and |r-s| = |1| =1 Yes
Let r=-1/2 and s=-1 then r-s =1/2 and |r-s| =1/2 Yes
Let r=-1/2 s = -3/4 then r-s = 1/4 and |r-s| = |1/4| = 1/4 Yes
Let r = 1/2 s =1/4 then r-s = 1/4 and |r-s| = 1/4 Yes
Let r=2 and s=1 then r-s = 2-1 = 1 and |r-s| =|1| = 1
So whether we pick negative integers, negative fractions, positive fractions, or positive integers for r and s we get a Yes answer we can mark sufficient
C