Hello there, 

Maximum marks are 400 marks where 200 marks belong to NATA and the other 200 belong to the board marks. 

To calculate your marks, you will have to divide your NATA score by 2 and add it to your board percentage. The result obtained are your marks. 

In your case, dividing 115/2 and summing it up with 90, your score is 147.5. Your score is better compared to many. Do apply for counselling 

Hope this helped you 

Thank you and keep asking:)