Boy,

       I'm just 16. I don't know how old you are, but I'm telling you, I think M.L.Khanna and R.D Sharma are not sufficient for IIT. Actually nothing is sufficient. IIT doesn't give questions from M.L.Khanna. The fact is that the more you practice maths the better you become, and books don't matter. I can name a thousand other books which are also good, but that doesn't help if your concepts and ideas are not clear. Of curse I'm not telling you not to do M.L.Khanna, but just the opposite, don't restrict yourself to M.L.khanna.

Do as many sums you can. In short, just practice, there's no short cut.

And it is the same for DCE or any other exam.

                           Hope you have understood.

                                                     

Please rate me if I have been of any help and if you think I'm correct.