Time needed

 I require that the student learn the school course very well, practice for competitions 3 hours daily for 5 days every week and play physical games 3-7 hours a week (not indoor video games) and study with me when needed. I do NOT want the student to solve numericals for 12 or 18 hours every day.
 

Comparison

You can select 3 or 4 students getting similar ranks in same school or college as your candidate. If after preparing with me, my student gets significantly better ranks in prestigious competitions, than those 3 or 4 students taking coaching elsewhere, I can take the fees. If my student gets worse ranks than those students or even similar ranks as those, you can take back the fees. I will not ask for any money in this case.