Hello Aspirant,

See it is little difficult to tell you about exact number of questions to be attempted to qualify JEE-Advance because maximum marks for JEE-Advance are not fixed and without knowing the maximum marks we cannot help you with the number of questions to be attempted to get qualified under any category.

Now if we go through previous year's minimum percentage required for your inclusion in Rank list than with OBC NCL category, a candidate needs 4.5% minimum in each subject mentioned in JEE-Advance and 15.75% in overall JEE-Advance.

https://engineering.careers360.com/articles/jee-advanced-cutoff-for-iits

I hope this information helps you.

Good Luck!!