Another day and yet another practice CAT - pretty much the same performance on the maths (timed out yet again), though aced the verbal. It's amazing the effect that time pressure has on performance, as looking back over the wrong/missed questions it's clear that most of them were actually 'easy' but were relying on the candidate to spot simple tricks...
Example sufficiency question:
What is a+b?
(1) (a^2-b^2) / (a-b) = 5
(2) (a+b)^2 = 25
answer = A. (a^2-b^2) simplifies to (a+b)(a-b), which divided by (a-b) leaves a+b=5 ... sufficient
(a+b)^2 = 25 means a+b= +5 or a+b= -5 ... insufficient