Hello there,
This depends on which course you are studying and in which college. With biology and mathematics you can go for B.Tech in Biotechnology. The scope of biotechnology has increased in this pandemic situation. Now if you complete your B.tech from top colleges like IITs, NITs and IIITs then your salary will be around 16 to 17 LPA. In some cases, you may also be offered upto 20 LPA. You can get more salary after your higher studies. The better degree and knowledge you have, the more is your salary. So choose your course and college wisely. And remember, whichever course you choose, you need to study well to get good grades and you will get a good job too.
Hope this information helps you.
Good luck!!