I have been prepairing for banking exams for the past 2 years. I follow number of online platform to study but I found gradestack.com or gradeup( app name) is the best. Other online platform are nowhere in the competition of it. You can post your queries on it and thousands of other students solve it. It is more or pess like a fb where we talk about study only. Daily GK updates, quizes, practicesets and other information related to exams are best things on this site. You can follow this website on your smartphone by just downloading its application named GradeUp from playstore.