Hi Adya, 

GATA Is the exam for you to give in GD GOENKA, 

the syllabus is as follows, 

ENGLISH 

Strong and Weak Arguments, Logical Sequence of Words, Logical Deduction, Statements Assumptions, Analogies, Course of Action, Statements and Conclusions, ETC

MATHEMATICS:

Time and Work, PROFIT AND LOSS, MENSURATION, TIME SPEED DISTANCE, GEOMETRY etc

GENERAL KNOWLEDGE: 

current affairs, world records, gk etc

ANALYTICAL REASONING :

Number series, clock matrix, venn diagram, ranking etc

I hope this helps you 

All the best take a good prep book for the same