To a large extent, this is a function of your initial state of readiness. The GMAT requires primarily two kinds of theoretical inputs : basic math (comparable to Grade 10 syllabus, but subject to severe pressures of time) and grammatically correct English. Both of these are skills acquired over many years of schooling, and the stronger your foundations in these subjects are, the easier it is for you to prepare. Typically, I recommend that you start preparing at least 3-4 months before your test date. During this time period, your preparation will be divided into two parts – the initial 1½-2 months when you concentrate on strengthening your foundations by delving into the topics of the GMAT syllabus, and the final two months or so when you will focus on sample GMAT tests that give you a feel of the actual computer adaptive GMAT.
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