can someone please help me with this its pass due and i have a lot of work i need to catch up for on math and i just need this one i can summit my work but i can't figure it out.

Problem 3 a bank charges a service fee of $7.50 per month for a checking account. a bank account has $85.00. if no money is deposited or withdrawn except the service charge, how many months until the account balance is negative