Hi !

With 315 marks, it is very difficult to get into any medical college in Mumbai. Because all medical colleges of Mumbai have cutoffs 450+ last year. And not even Mumbai, the whole Maharashtra private medical colleges have very high cutoffs. So 315 marks are very less to get a seat in private medical colleges of the state. 

Last year the mumbai colleges have 486 and 497 cutoffs for regional and state quotas respectively.

Check out the following website for more detailed information related to cutoffs.

https://medicine.careers360.com/articles/neet-cutoff-maharashtra