What does IIT do when two or more candidates share the same aggregate score?

When two candidates share the same aggregate score, the one with more marks in Mathematics (followed by the scores in Physics and Chemistry) is given a higher rank. In case the scores in all the three subjects are similar, both the candidates will share the same rank.  For more details, visit http://www.askiitians.com/iit-jee/jee-advanced/2013/counseling/.

As per my knowledge if this case happens then the marks of board exams come into use.please like it if you are satisfied !!!