Oil data test is not really hard.You just have to be fast cos its computer based and you get to see ur scores immediately after the test..just read basic GMAT maths to enhance ur speed wud do... There's a tricky part in d english questions...u might see a question like,
A.Haric
B.Bltea
C.Ugr
D.Ngmao
E.Rtuncai
And u wud be told to spot the odd one out...u need to look well cos those r words that relate but spelt wrongly
Chair
Table
Rug
mango
Curtain...
The odd one is mango thus the answer is
Lots of questions like dat..believe me..d day I wrote dis test,I was d only one dat noticed and answered dem correctly from about 20 of us dat sat for it as we all discussed after d exam...and only one dat scored above 100(115 to be precise) so crack dis and d rest na akamu!