Testbook.com is best website for online preperation by self study. It gives various tests on various competitive exams like gate, railway ntpc, alp, group d, ssc etc. When any exam test in real is comes near they give test series for practice. The test series available on it, is free as well as paid.It gives practice quiz exam that is very helpful according to exam point of view. The exam is related to subjects. I also use this website for preparation of railway alp. I was also used this for ssc je exam. Currently railway quize test are run by thia website. Out of which some are practiced. The time given to exam on it, is total time that given in real exam. This is very helpfull for me.