solving a quant qst takes atleast 3 mins for me. Sometimes after three minutes I'm not arriving at answers eventhough I'm very well aware of that question concept. So ending up attempting only 5 questions. How to improve from here??

Don't focus on the time, focus on whether or not you are understanding the concept's. In CAT usually 10% Quant questions are such that one requires high logic and calculations to work them out. But we still have more than 3/4 of questions which can be solved quickly with good effort, provided one understands the concept. Knoweldge of subject, simple clear concepts (like odd + odd = even, if distance is same time and speed are inversely related, etc.) and their application is the most important. If you strive for this, speed will come naturally come. So in these last days just build on your concept, as solving 2 more questions wrongly in CAT < solving 2 less questions correctly.

same happened with me, I would suggest you to revise all the concepts of quants again and then attempt another mock