You might need nothing less than 95-97 percentile. This is because FMS Delhi usually has the highest cut offs for its 200 seat intake. The selection process includes 3 stage method. They are:

Eligibility Criteria
Group Discussion and Personal Interview
Final Selection

The basic eligibility criteria remains 50% aggregate for General Category in Graduation and 45% for Reserved Categories or equivalent CGPA from any recognised University. The percentiles in CAT are considered for the further rounds. In 2018, the weightage given for various sections of CAT have been as follows:

QA: 30%
DILR: 30%
VARC: 40%
An additional 3 marks are added to the Composite score in case of women for shortlisting. This score is used only for shortlisting Candidates for Personal Interview. The weightage for Final selection is as follows:
Personal Interview: 15%
CAT score: 60%
Group Discussion: 10%
Extempore: 5%
10th marks: 5%
12th marks: 5%
An additional 3 marks of the maximum aggregate will be added to the women candidates who have attended the Interview. Now with all this process, the cut offs is an important issue to be discussed. Previously FMS used to consider overall CAT score for shortlisting. However since the past 2 years, FMS has been giving sectional preference and weightage. VARC occupies the top position with 40% weightage. A Candidate with at least 97 sectional weightage will be shortlisted at FMS. So it is important to focus more on VARC section while not leaving other sections.