Exemption criteria

The exemption is valid for the 3 consecutive attempts irrespective of whether you appear in them or not. 

I meant go say that I m gonna to appear in may nd want to knw that out of 4 I hv 2 strong subjects if I get exemption in those nd don't sit In other 2 will i b granted exemption. If I score??

No you are guessing it wrong. If u think that u will get 60 or above in 1 paper or more and u want to avail exemption in that paper, u need to APPEAR in all the remaining papers of that group. In other words, if u r absent in even 1 paper of a group, u WON'T be eligible to avail exemptionin in ANY PAPER of that group.