If the family decides to fly, they know that they will need a rental car for at least part of their trip. Gabriela and Luis estimate a budget of $315 for rental car expenses. One rental car company charges $55 per day and $35 in taxes and fees. They also estimate that they will spend $15 per day on gas. Gabriela wrote the equation (55d+35)+15d=315 to determine the number of days the family can rent a car from this company. How many days could the Morales family rent a car if they choose this rental car company with their estimated budget?