hi,

see you can not get any direct admission in tier 1 colleges by your 12th score, you may get admission in tier 3 colleges, where there is less number of faculty, no good placement opportunity, number of student is less, after passing btech you will not get any good work opportunity. and as for 12th score, you will not eligible for  most of the companies, because most mncs, government psus, top core companies like tata steel, tcs, cognizant all wants 60% marks in 10+2.