Are B.Tech ECE graduates eligible for M.Tech. CSE in all/most universities, based only on GATE score? Which universities don't allow this?

IIT Bhubaneswar offer regular course admission based on GATE scores only. For sponsored category candidates with 3+ years experience or graduates from IITs with required aggregate, selection may get done without GATE scores. 

Surely, GATE previous year papers are very useful in preparation for the exam. It will help in understanding the overall exam structure, paper pattern and subejct-wise weightage of topics. Every GATE aspirant must solve GATE previous year papers. 

GATE previous year answer key with solutions can be checked on Shiksha page. These previous year question paper solutions have been prepared by subejct experts and will help GATE aspirants to prepare for the exam.

The provisional answer key of GATE is the preliminary answer key provided by the organising institute which is kept open for review and challenge by students. After the review, the final answer key is released.

No, the question papers released by coaching institutes are prepared using memory based questions from students who appear in the exam. They are not the actual papers. The official/actual papers are released only by the organising institute.