Dear Shreya, you haven't mentioned which entrance exam you are enquiring about. But if the system has accepted 2 registrations for 1 gmail id, there would be a confusion during the communication. Under normal circumstances, one email id for 2 registrations is not acceptable. Because one of the applications might be cancelled. But please do help us with the entrance exam you are talking about and we shall help you with the helpdesk email id to sort out the issue with the authorities.