If the payment is done on May 20th, 2018, will the admissions are there for 2018 entrance only or for 2019?

Simply make your resume/CV and application for teaching position and school or colleges. If you have good way of teaching and explaining of topics, definitely you will get any good positions. So don't wait, go any apply.

The MBA placement in gandhi institute of technology is Average, its average salary is near 1.8Lacs and it can go to 2.5 Lacs per annum.

According to students who have appeared in PESSAT in previous years, it is not extraordinarily difficult to crack it. Preparation can be done alongside other national level entrance exams. For example, if you are preparing for JEE Main, then it's preparation will be sufficient for PES University entrance exam also. In addition, there is an English section also, so just focus on preparing that in addition.

Yes, it is actually possible for you to download previous question papers online. I suggest you this link complied by Shiksha, where in you get access to question papers of various years PESSAT exams. It has all the required details. For you. I wish you all the best with this and I hope this was helpful. Thank you. https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/university/pes-university/exams/amp/pessat-mba/question-papers&ved=2ahUKEwi-xKnM8b7aAhVLrY8KHa8tA90QFjAAegQICBAB&usg=AOvVaw0lCa1_kyB5YLh7lW3cvdyW&cf=1.