I have scored 68.4% in 10th,81% in 12th and 66.6% in B.Sc in hotel management. Being a SC candidate what should be my target in CAT

As you have a average academic background so you need to aim for a better percentile in comparison so as to overcome the marks loss due to academic records. You need to know that after CAT exam every IIMs or college you have applied to call students for interview and WSAT round, makes a merit list which is based on your aggregate score which comprises of many factors such as CAT marks, 10th 12th and graduation percentage, work experience, engineer or non engineer, gender with different weightages for different colleges. Generally overall weightage for 10th 12th and graduation is around 10-25%.

For getting a call from top 3 IIMs i.e. IIM A, B and C you need to score atleast above 93+ percentile. Target for 95+ percentile to increase your probability of getting a call and conversion.

For other old IIMs like IIM L, K, I you need to score above 85+ percentile. Target for 90+ percentile to increase probability of conversion.

For new IIMs anything above 80+ percentile will mos probably will get you call. If you are applying for other b-schools like FMS, JBIMS then target 90+ percentile to get a call and inctease the conversion probability.

All the best for your preparations and exams!!