For Compulsory Kannada and English Need not spend much time,except for reading as its only of 10th class Level
If you have Long written Kannada then may be just write a page or so whenever time permits. No need to Panic as its only Qualifying Marks and at the same time should not take too light also...
Just be in touch with the grammar.
For English from magazine wizard can find some help.
On Conclusion can say that Grammar Correction + Reading news papers will help in English language Paper and for Kannada News Paper + some writing will do a good job.