A local car dealership is holding a year-end event because new car models have just been released. Declan has $35,000 to spend on a car. The car Declan decides to buy for his family costs $35,000 . However, it is part of the year-end event, which means he receives a 15% discount on the new car. Declan plans to put the money he saves on the car into a new bank account. The bank account has a yearly simple interest rate of 4% , paid at the end of each year. If Declan does not add any other money to this bank account, it will take how many years for Declan's bank account to reach $6,720 .