What about the probability of getting Physics or Chemistry honours at DU with 78 and 79 in the respective subjects and 55 in Maths? (84.6%)
The criteria for admission in chemistry Hons and physics Hons is the aggregate percentage of PCM marks and to get admission in chemistry Hons and physics Hons, at least 88% marks are required ( for general category students). Your PCM percentage is much less than the expected cutoffs. So, unfortunately, your chances of getting admission in chemistry Hons and physics Hons is very low.