Will I have to face any problem during placement? I got 85% in physics+che+eng+physical education+cs. And have 79.8% in physics+chemistry+maths+english+physical education. Which % is calculated for placement eligibility?

It is unlikely that you will face any issues during the placement process. Most of the companies look for a combination of factors, including the overall percentage. But your percentage demonstrates a good academic performance. The specific percentage accepted by the placement companies also depends on the company and the role they are hiring for. Some companies can have a GPA or percentage requirement, while others completely focus on specific subject areas and skills.