How many rows are vacant?

The total number of rows was thrice as that of Anuj's row number. Not more than 15 persons were seated in the theatre. Chunnu was seated in row number 10. With the second hint it is clear that there were maximum of 15 persons or say 15 rows in the theatre, because one person sits in one row. With the third hint it is clear that Anuj's row number was more than 3, because one of the persons Chunnu was in row number 10. Case 1: When Anuj's seat number is 5 Case 2: When Anuj's seat number is 4 Eri was immediyately above Diya. Diya's row number was six times as that of Vani's row number. Case 1 breaks into one more case i.e. Case 1A Case 2: Firoj was seated in a prime numbered row somewhere above Eri and was not neighbouring Chunnu. Case 2 fails, as the only prime numbered row above Eri is 11 , which is neighbouring Chunnu. Case 1A fails, as there is no prime numbered row above Eri.