if i do 3 questions in codechef contest and next time i do 5 questions will it decrease my rating?
you have read the following rules of that particular contest .
No, your rating on CodeChef is typically based on your performance in individual contests. If you solve more questions correctly in a contest, it’s generally expected to have a positive impact on your rating, regardless of whether it’s 3 or 5 questions. However, the specific changes to your rating will depend on the contest and the performance of other participants.