Twenty five sets of problems on Data Interpretation one each for the DI sections of $25$ CATALYST tests were prepared by the AMS research team. The DI section of each CATALYST contained $50$ questions of which exactly $35$ questions were unique, i.e. they had not been used in the DI section of any of the other $24$ CATALYSTs. What could be the maximum possible number of questions prepared for the DI sections of all the $25$ CATALYSTs. What could be the maximum possible number of questions prepared for the DI sections of all the $25$ CATALYSTs put together?