Science

In combination, you cannot get any college because you can complete your graduation in a single field from all of these either in physics or chemistry or maths.
All three could not be available in B.Sc combined. But, yes, if you take B.Sc maths, there would be combination of physics and maths both.
Ho

Career prospects and job opportunities:
Food technology is a vast industry and so are the career opportunities. Food technologists can have a bright career in hotels, quality control departments, food industries, packaging industries, hospitals, distilleries, soft drink factories and rice mills, etc.

You need to clear the entrance examination of the university.

Please check for your eligibility to pursue this course from Vivekananda College at the link provided below. Admission process for this course is also mentioned at this link.
https://www.shiksha.com/science/course/b-sc-hons-in-mathematics-vivekananda-college-vivek-vihar-delhi-258809

Basic eligibility to pursue this course is that Candidate must have completed Graduation degree with Zoology as honours Subject. Admission is based on the marks obtained in graduation. Interested candidates can apply online/offline with required information. Regards.

I don't think NID provides any master's courses and if any institute provides any master's courses that is M.Des.

Yes. Anyone above the age of 15 can apply for FX School courses.