X + 2(Y+Z) = 13
From (A)
Z = 1 , Y = 2 , X =7
Z = 2, Y = 3 , X =3 --> fails
so Z = 1, hence sufficient
from (B)
Z = 1 , Y = 2 , X =7
Z = 2, Y = 3 , X =3
Z = 3, Y = 2 , X =3
so not sufficient to find a unique value of Z
ds 2
This topic has expert replies
Source: Beat The GMAT — Data Sufficiency |

















